View Filing Data

(900)

4,988

6,813

13,929

Charges related to refinancing

(2,919)

Operating earnings

^[3]

210,811

^[2]

183,814

^[1]

114,297

Interest expense

16,484

22,038

22,658

8,155

Other (income) expense, net

3,068

2,177

4,384

Earnings before income taxes

191,259

151,444

87,255

Income tax expense

47,292

38,018

24,951

Net losses attributable to noncontrolling interests

143,967

113,426

^[4]

62,304

(36)

Net earnings attributable to EnerSys stockholders

$ 144,003

$ 113,426

$ 62,304

Net earnings per common share attributable to EnerSys stockholders:

Basic

$ 2.95

$ 2.30

$ 1.29

Diluted

$ 2.93

$ 2.27

$ 1.28

Weighted-average shares of common stock outstanding:

Basic

48,748,205

49,376,132

48,122,207

Diluted

49,216,035

50,044,246

48,834,095

[1]	Included in Operating earnings were restructuring charges of $723, $2,750, $1,754 and $1,586 for the first, second, third and fourth quarters of fiscal 2011, respectively.
[2]	Included in Operating earnings were restructuring charges of $410, $902, $1,440 and $2,236 for the first, second, third and fourth quarters of fiscal 2012, respectively. Operating earnings also included a legal proceedings settlement income of $900, in the second quarter of fiscal 2012.
[3]	The Company does not allocate interest expense or other (income) expense to the reportable segments.
[4]	Included in Net earnings of fiscal 2011 were charges related to refinancing of $8,155 in the fourth quarter of fiscal 2011.

Consolidated Statements Of Changes In Stockholders' Equity - USD ($)
$ in Thousands

Common Stock [Member]

Paid-in Capital [Member]

Treasury Stock [Member]

Retained Earnings [Member]

Accumulated Other Comprehensive Income [Member]

Total EnerSys Stockholders' Equity [Member]

Non-Controlling Interest [Member]

Total

Balance at Mar. 31, 2009

$ 498

$ 414,292

$ (19,800)

$ 241,106

$ 34,055

$ 670,151

$ 4,242

$ 674,393

Exercise of stock options

6,964

5,036

5,042

Tax benefit from stock options

2,287

Increase in noncontrolling interest

Pension funded status adjustment, net of tax

62,304

Other comprehensive income:

(685)

Unrealized income (losses) on derivative instruments, net of tax

2,626

Foreign currency translation adjustment

31,208

Comprehensive income

95,453

Balance at Mar. 31, 2010

504

428,579

(19,800)

303,410

67,204

779,897

4,327

784,224

Exercise of stock options

9,056

17,880

17,894

Tax benefit from stock options

6,082

Increase in noncontrolling interest

335

Pension funded status adjustment, net of tax

113,426

^[1]

Other comprehensive income:

1,967

Unrealized income (losses) on derivative instruments, net of tax

9,470

Foreign currency translation adjustment

36,539

Comprehensive income

161,402

Balance at Mar. 31, 2011

518

461,597

(19,800)

416,836

115,180

974,331

4,662

978,993

Exercise of stock options

11,585

970

974

Tax benefit from stock options

1,772

Purchase of common stock

(58,383)

Acquisition of noncontrolling interest

(1,000)

Noncontrolling interests attributable to the consolidation of acquisitions

8,260

Pension funded status adjustment, net of tax

144,003

(36)

143,967

Other comprehensive income:

(5,470)

Unrealized income (losses) on derivative instruments, net of tax

(3,261)

Foreign currency translation adjustment

(32,356)

(160)

(32,516)

Comprehensive income

102,916

(196)

102,720

Balance at Mar. 31, 2012

$ 522

$ 474,924

$ (78,183)

$ 560,839

$ 74,093

$ 1,032,195

$ 12,726

$ 1,044,921

[1]	Included in Net earnings of fiscal 2011 were charges related to refinancing of $8,155 in the fourth quarter of fiscal 2011.

Consolidated Statements Of Changes In Stockholders' Equity (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
Consolidated Statements Of Changes In Stockholders' Equity [Abstract]
Pension funded status adjustment, tax expense (benefits)	$ (1,841)	$ 794	$ (367)
Unrealized income on derivative instruments, tax expense (benefits)	$ (1,909)	$ 5,251	$ 1,421

Tax effects of the increase (decrease) to accumulated comprehensive income during the period related to benefit plans that is attributable to the parent entity.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph 30
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph 29
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 45
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=6921628&loc=SL4569643-111683

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 45
-Paragraph 19
-URI http://asc.fasb.org/extlink&oid=6921628&loc=SL4569616-111683

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (c)(3)
-URI http://asc.fasb.org/extlink&oid=6921930&loc=SL4573702-111684

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph 38
-Subparagraph c(3)
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Cash flows from operating activities

Consolidated Statements Of Cash Flows - USD ($)
$ in Thousands

12 Months Ended

Mar. 31, 2012

Mar. 31, 2011

Mar. 31, 2010

Adjustments to reconcile net earnings to net cash provided by operating activities:

$ 143,967

$ 113,426

^[1]

$ 62,304

Depreciation and amortization

50,360

44,393

44,851

Derivatives not designated in hedging relationships:

Net losses

1,083

Cash settlements

(3,763)

Provision for doubtful accounts

1,395

1,513

2,712

Deferred income taxes

(3,227)

(3,064)

6,975

Non-cash interest expense

7,983

7,776

7,163

Write-off of deferred financing fees

11,585

9,056

6,964

2,308

Gain on disposal of fixed assets

(2,919)

(432)

(912)

Changes in assets and liabilities, net of effects of acquisitions:

Accounts receivable

7,106

(61,892)

(7,303)

Inventory

(19,655)

(67,250)

(23,445)

Prepaid expenses and other current assets

8,834

(15,658)

(1,075)

Other assets

(955)

(2,552)

(1,218)

Accounts payable

(12,377)

42,422

59,116

Accrued expenses

13,505

(3,822)

(5,816)

Other liabilities

(1,213)

9,803

(10,795)

Net cash provided by operating activities

204,196

76,459

136,602

Cash flows from investing activities

Capital expenditures

(48,943)

(59,940)

(45,111)

Purchase of businesses, net of cash acquired

(24,553)

(32,200)

(33,242)

Proceeds from disposal of property, plant, and equipment

479

1,109

Net cash used in investing activities

(73,420)

(91,661)

(77,244)

Cash flows from financing activities

Net (decrease) increase in short-term debt

(462)

3,084

(7,436)

Proceeds from revolving credit borrowings

111,550

100,000

Repayment of revolving credit borrowings

(132,150)

Proceeds from long-term debt - other

6,112

Payments of long-term debt - other

(308)

(212,238)

(25,243)

Deferred financing fees incurred in connection with refinancing prior credit facility

(3,500)

Capital lease obligations and other

(1,375)

(111)

878

Net effect from exercising of stock options and vesting of equity awards

974

17,894

5,042

Excess tax benefits from exercise of stock options and vesting of equity awards

1,772

6,082

2,287

Purchase of treasury stock

(58,383)

Net cash used in financing activities

(78,382)

(82,677)

(24,472)

Effect of exchange rate changes on cash

(773)

5,706

2,995

Net increase (decrease) in cash and cash equivalents

51,621

(92,173)

37,881

Cash and cash equivalents at beginning of year

108,869

201,042

163,161

Cash and cash equivalents at end of year

$ 160,490

$ 108,869

$ 201,042

[1]	Included in Net earnings of fiscal 2011 were charges related to refinancing of $8,155 in the fourth quarter of fiscal 2011.

Summary Of Significant Accounting Policies	12 Months Ended
Summary Of Significant Accounting Policies	Mar. 31, 2012
Summary Of Significant Accounting Policies [Abstract]
Summary Of Significant Accounting Policies	1. Summary of Significant Accounting Policies *Description of Business* EnerSys and its predecessor companies have been manufacturers of industrial batteries for over 100 years. EnerSys is a global leader in stored energy solutions for industrial applications. The Company manufactures, markets and distributes industrial batteries and related products such as chargers, power equipment and battery accessories, and provides related after-market and customer-support services for industrial batteries. *Principles of Consolidation* The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries and any partially-owned subsidiaries that the Company has the ability to control. Control generally equates to ownership percentage, whereby investments that are more than 50% owned are generally consolidated, investments in affiliates of 50% or less but greater than 20% are generally accounted for using the equity method, and investments in affiliates of 20% or less are accounted for using the cost method. All intercompany transactions and balances have been eliminated in consolidation. *Foreign Currency Translation* Results of foreign operations are translated into U.S. dollars using average exchange rates during the period. The assets and liabilities are translated into U.S. dollars using exchange rates as of the balance sheet date. Gains or losses resulting from translating the foreign currency financial statements are accumulated as a separate component of accumulated other comprehensive income ("AOCI") in EnerSys' stockholders' equity and noncontrolling interests. Transaction gains and losses resulting from exchange rate changes on transactions denominated in currencies other than the functional currency of the applicable subsidiary are included in the Consolidated Statements of Income, within "Other (income) expense, net", in the year in which the change occurs. *Revenue Recognition* The Company recognizes revenue when the earnings process is complete. This occurs when risk and title transfers, collectibility is reasonably assured and pricing is fixed and determinable. Shipment terms are either shipping point or destination and do not differ significantly between the Company's business segments. Accordingly, revenue is recognized when risk and title are transferred to the customer. Amounts invoiced to customers for shipping and handling are classified as revenue. Taxes on revenue producing transactions are not included in net sales. The Company recognizes revenue from the service of its reserve power and motive power products when the respective services are performed. Accruals are made at the time of sale for sales returns and other allowances based on the Company's historical experience. *Freight Expense* Amounts billed to customers for outbound freight costs are classified as sales in the consolidated statements of income. Costs incurred by the Company for outbound freight costs to customers, inbound and transfer freight are classified in cost of goods sold. *Warranties* The Company's products are warranted for a period ranging from one to twenty years for reserve power batteries and for a period ranging from one to seven years for motive power batteries. The Company provides for estimated product warranty expenses when the related products are sold. The assessment of the adequacy of the reserve includes a review of open claims and historical experience. *Cash and Cash Equivalents* Cash and cash equivalents include all highly liquid investments with an original maturity of three months or less when purchased. *Concentration of Credit Risk* Financial instruments that subject the Company to potential concentration of credit risk consist principally of short-term cash investments and trade accounts receivable. The Company invests its cash with various financial institutions and in various investment instruments limiting the amount of credit exposure to any one financial institution or entity. The Company has bank deposits that exceed federally-insured limits. In addition, certain cash investments may be made in U.S. and foreign government bonds, or other highly rated investments guaranteed by the U.S. or foreign governments. Concentration of credit risk with respect to trade receivables is limited by a large, diversified customer base and its geographic dispersion. The Company performs ongoing credit evaluations of its customers' financial condition and requires collateral, such as letters of credit, in certain circumstances. *Accounts Receivable* The Company maintains allowances for doubtful accounts for estimated losses resulting from the inability of customers to make required payments. The allowance is based on management's estimate of uncollectible accounts, analysis of historical data and trends, as well as reviews of all relevant factors concerning the financial capability of its customers. Accounts receivable are considered to be past due based on how payments are received compared to the customer's credit terms. Accounts are written off when management determines the account is uncollectible. *Inventories* Inventories are stated at the lower of cost or market. Cost is determined using the first-in, first-out (FIFO) method. The cost of inventory consists of material, labor, and associated overhead. *Property, Plant, and Equipment* Property, plant, and equipment are recorded at cost and include expenditures that substantially increase the useful lives of the assets. Depreciation is provided using the straight-line method over the estimated useful lives of the assets as follows: 10 to 33 years for buildings and improvements and 3 to 15 years for machinery and equipment. Maintenance and repairs are expensed as incurred. Interest on capital projects is capitalized during the construction period. Goodwill and Other Intangible Assets The Company records the excess of purchase price over the fair value of the tangible and identifiable intangible assets acquired as goodwill. Goodwill and indefinite-lived trade names are tested for impairment at least annually and whenever events or circumstances occur indicating that a possible impairment may have been incurred. The Company utilizes financial projections of its business segments, certain cash flow measures, as well as its market capitalization in its determination of the fair value of these assets. Finite-lived assets such as purchased and licensed technology, patents and customer lists are amortized over their estimated useful lives, generally over periods ranging from 3 to 20 years. The Company reviews the carrying values of these assets for possible impairment whenever events or changes in circumstances indicate that the carrying value of an asset may not be recoverable based on undiscounted estimated cash flows expected to result from its use and eventual disposition. The Company continually evaluates the reasonableness of the useful lives of these assets. *Impairment of Long-Lived Assets* The Company reviews the carrying values of its property and equipment for possible impairment whenever events or changes in circumstances indicate that the carrying value of an asset may not be recoverable based on undiscounted estimated cash flows expected to result from its use and eventual disposition. The factors considered by the Company in performing this assessment include current operating results, trends and other economic factors. In assessing the recoverability of the carrying value of the property and equipment, the Company must make assumptions regarding future cash flows and other factors. If these estimates or the related assumptions change in the future, the Company may be required to record an impairment loss for these assets. *Environmental Expenditures* The Company records a loss and establishes a reserve for environmental remediation liabilities when it is probable that an asset has been impaired or a liability exists and the amount of the liability can be reasonably estimated. Reasonable estimates involve judgments made by management after considering a broad range of information including: notifications, demands or settlements that have been received from a regulatory authority or private party, estimates performed by independent engineering companies and outside counsel, available facts existing and proposed technology, the identification of other potentially responsible parties, their ability to contribute and prior experience. These judgments are reviewed quarterly as more information is received and the amounts reserved are updated as necessary. However, the reserves may materially differ from ultimate actual liabilities if the loss contingency is difficult to estimate or if management's judgments turn out to be inaccurate. If management believes no best estimate exists, the minimum probable loss is accrued. Derivative Financial Instruments The Company utilizes derivative instruments to mitigate volatility related to interest rates, lead prices and foreign currency exposures. The Company does not hold or issue derivative financial instruments for trading or speculative purposes. The Company recognizes derivatives as either assets or liabilities in the accompanying balance sheet and measures those instruments at fair value. Changes in the fair value of those instruments are reported in AOCI if they qualify for hedge accounting or in earnings if they do not qualify for hedge accounting. Derivatives qualify for hedge accounting if they are designated as hedge instruments and if the hedge is highly effective in achieving offsetting changes in the fair value or cash flows of the asset or liability hedged. Effectiveness is measured on a regular basis using statistical analysis and by comparing the overall changes in the expected cash flows on the lead and foreign currency forward contracts with the changes in the expected all-in cash outflow required for the lead and foreign currency purchases. This analysis is performed on the initial purchases quarterly that cover the quantities hedged. Accordingly, gains and losses from changes in derivative fair value of effective hedges are deferred and reported in AOCI until the underlying transaction affects earnings. The Company has commodity, foreign exchange and interest rate hedging authorization from the Board of Directors and has established a hedging and risk management program that includes the management of market and counterparty risk. Key risk control activities designed to ensure compliance with the risk management program include, but are not limited to, credit review and approval, validation of transactions and market prices, verification of risk and transaction limits, portfolio stress tests, sensitivity analyses and frequent portfolio reporting, including open positions, determinations of fair value and other risk management metrics. Market risk is the potential loss the Company and its subsidiaries may incur as a result of price changes associated with a particular financial or commodity instrument. The Company utilizes forward contracts, and swaps as part of its risk management strategies, to minimize unanticipated fluctuations in earnings caused by changes in commodity prices, interest rates and/or foreign currency exchange rates. All derivatives are recognized on the balance sheet at their fair value, unless they qualify for Normal Purchase Normal Sale. Credit risk is the potential loss the Company may incur due to counterparty's non-performance. The Company is exposed to credit risk from interest rate, foreign currency and commodity derivatives with financial institutions. The Company has credit policies to manage their credit risk, including the use of an established credit approval process, monitoring of counterparty positions and the use of master netting agreements. The Company has elected to offset net derivative positions under master netting arrangements. The Company does not have any positions involving cash collateral (payables or receivables) under a master netting arrangement as of March 31, 2012 and 2011. The Company does not have any credit-related contingent features associated with their derivative instruments. *Fair Value of Financial Instruments* The fair value of the Company's cash and cash equivalents, accounts receivable and accounts payable approximate carrying value due to their short maturities. The fair value of the Company's $350,000 senior secured revolving credit facility ("2011 Credit Facility"), the 75,000 Chinese Renminbi ("RMB") credit facility ("China Term Loan"), the 273,780 Indian Rupee ("INR") term loan ("India Term Loan") and short-term debt approximate their carrying value, as they are variable rate debt and the current terms are comparable to market terms as of the balance sheet dates and are classified as Level 2. The fair value amounts of the Company's $172,500 senior unsecured 3.375% convertible notes ("Convertible Notes") represent the trading values of the Convertible Notes which is based upon quoted market prices and are classified as Level 2. Fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (an exit price). The Company and its subsidiaries use, as appropriate, a market approach (generally, data from market transactions), an income approach (generally, present value techniques and option-pricing models), and/or a cost approach (generally, replacement cost) to measure the fair value of an asset or liability. These valuation approaches incorporate inputs such as observable, independent market data and/or unobservable data that management believes are predicated on the assumptions market participants would use to price an asset or liability. These inputs may incorporate, as applicable, certain risks such as nonperformance risk, which includes credit risk. Lead contracts, foreign currency contracts and interest rate contracts generally use an income approach to measure the fair value of these contracts, utilizing readily observable inputs, such as forward interest rates (e.g., London Interbank Offered Rate—"LIBOR") and forward foreign currency exchange rates (e.g., GBP and euro) and commodity prices (e.g. London Metals Exchange), as well as inputs that may not be observable, such as credit valuation adjustments. When observable inputs are used to measure all or most of the value of a contract, the contract is classified as Level 2. Over-the-counter (OTC) contracts are valued using quotes obtained from an exchange, binding and non-binding broker quotes. Furthermore, the Company obtains independent quotes from the market to validate the forward price curves. OTC contracts include forwards, swaps and options. To the extent possible, fair value measurements utilize various inputs that include quoted prices for similar contracts or market-corroborated inputs. When unobservable inputs are significant to the fair value measurement, a contract is classified as Level 3. The Company did not have any Level 3 positions at March 31, 2012 or March 31, 2011. Additionally, Level 2 fair value measurements include adjustments for credit risk based on the Company's own creditworthiness (for net liabilities) and its counterparties' creditworthiness (for net assets). The Company assumes that observable market prices include sufficient adjustments for liquidity and modeling risks. The Company did not have any contracts that transferred between Level 2 and Level 3 as well as Level 1 and Level 2. *Income Taxes* The Company accounts for income taxes in accordance with the Financial Accounting Standards Board ("FASB") guidance, which requires deferred tax assets and liabilities be recognized using enacted tax rates to measure the effect of temporary differences between book and tax bases on recorded assets and liabilities. FASB guidance also requires that deferred tax assets be reduced by a valuation allowance, if it is more likely than not some portion or all of the deferred tax assets will not be recognized. The Company evaluates on a quarterly basis its ability to realize deferred tax assets by assessing its valuation allowance and by adjusting the amount of such allowance, if necessary. The factors used to assess the likelihood of realization are forecasts of future taxable income and available tax planning strategies that could be implemented to realize the net deferred tax assets. In accordance with FASB guidance on accounting for uncertainty in income taxes, the Company evaluates tax positions to determine whether the benefits of tax positions are more likely than not of being sustained upon audit based on the technical merits of the tax position. For tax positions that are more likely than not of being sustained upon audit, the Company recognizes the largest amount of the benefit that is greater than 50% likely of being realized upon ultimate settlement. For tax positions that are not more likely than not of being sustained upon audit, the Company does not recognize any portion of the benefit. If the more likely than not threshold is not met in the period for which a tax position is taken, the Company may subsequently recognize the benefit of that tax position if the tax matter is effectively settled, the statute of limitations expires, or if the more likely than not threshold is met in a subsequent period. *Deferred Financing Fees* Debt issuance costs that are incurred by the Company in connection with the issuance of debt are deferred and amortized to interest expense over the life of the underlying indebtedness, adjusted to reflect any early repayments. Retirement Plans The Company accounts for retirement plans in accordance with FASB guidance on employers' accounting for defined benefit pension benefit plans, which requires an entity to recognize in its statement of financial position an asset for a defined benefit postretirement plan's overfunded status or a liability for a plan's underfunded status, and to measure a defined benefit postretirement plan's assets and obligation that determine its funded status as of the end of the balance sheet date. The Company uses certain assumptions in the calculation of the actuarial valuations of its defined benefit plans. These assumptions include discount rate, rates of increase in compensation levels and expected long-term rates of return of plan assets. If actual results are less favorable than those projected by the Company, additional expense may be required. Stock-Based Compensation Plans The Company accounts for stock compensation in accordance with FASB guidance, which requires the Company to measure the cost of employee services received in exchange for the award of an equity instrument based on the grant-date fair value of the award, with such cost recognized over the applicable vesting period. In addition, the guidance requires an entity to provide certain disclosures in order to assist in understanding the nature of share-based payment transactions and the effects of those transactions on the financial statements. Market Share Units The fair value of the market share units is estimated at the date of grant using a binomial lattice model with the following assumptions: a risk-free interest rate, dividend yield, time to maturity and expected volatility. These units vest and are settled in common stock on the third anniversary of the date of grant. Market share units are converted into between zero and two shares of common stock for each unit granted at the end of a three-year performance cycle. The conversion ratio is calculated by dividing the average closing share price of the Company's common stock during the ninety calendar days immediately preceding the vesting date by the average closing share price of the Company's common stock during the ninety calendar days immediately preceding the grant date, with the resulting quotient capped at two. This quotient is then multiplied by the number of market share units granted to yield the number of shares of common stock to be delivered on the vesting date. The Company recognizes compensation expense using the straight-line method over the life of the market share units. Restricted Stock Units The fair value of restricted stock units is based on the closing market price of the Company's common stock on the date of grant. These awards generally vest, and are settled in common stock, at 25% per year, over a four-year period from the date of grant. The Company recognizes compensation expense using the straight-line method over the life of the restricted stock units. Stock Options The fair value of the options granted is estimated at the date of grant using the Black-Scholes option-pricing model utilizing assumptions based on historical data and current market data. The assumptions include expected term of the options, risk-free interest rate, expected volatility, and dividend yield. The expected term represents the expected amount of time that options granted are expected to be outstanding, based on historical and forecasted exercise behavior. The risk-free rate is based on the rate at grant date of zero-coupon U.S. Treasury Notes with a term equal to the expected term of the option. Expected volatility is estimated using historical volatility rates based on historical weekly price changes. The Company's dividend yield is based on historical data. The Company recognizes compensation expense using the straight-line method over the vesting period of the options. *Earnings Per Share* Basic earnings per common share ("EPS") are computed by dividing net earnings available to common stockholders by the weighted average number of common shares outstanding for the period. Diluted EPS reflects the potential dilution that would occur if securities or other contracts to issue common stock were exercised or converted into common stock. At March 31, 2012, 2011 and 2010, the Company had outstanding stock options, restricted stock units, market share units and Convertible Notes, which could potentially dilute basic earnings per share in the future. *Segment Reporting* FASB guidance defines that a segment for reporting purposes is based on the financial performance measures that are regularly reviewed by the chief operating decision maker to assess segment performance and to make decisions about a public entity's allocation of resources. Based on this guidance, the Company reports its segment results based upon the three geographical regions of operations—Americas, Europe and Asia. *New Accounting Pronouncements* In June 2011, the FASB issued authoritative guidance requiring entities to present net income and other comprehensive income either in a single continuous statement of comprehensive income or in two separate but consecutive statements and eliminated the option to present components of other comprehensive income as part of the statement of shareholders' equity. This guidance will be effective for the Company in the first quarter of fiscal 2013 and is not expected to have an impact on its financial statements other than the change in presentation. In September 2011, the FASB issued revised guidance to simplify how entities test goodwill for impairment. The amendments will permit an entity to first assess qualitative factors to determine whether it is necessary to perform the two-step goodwill impairment test. An entity will no longer be required to calculate the fair value of a reporting unit unless the entity determines, based on a qualitative assessment that it is more likely than not that its fair value is less than its carrying amount. The amendments are effective for annual and interim goodwill impairment tests performed for fiscal years beginning after December 15, 2011, with early adoption permitted. The Company plans to adopt this guidance for its annual goodwill impairment test performed in fiscal 2013 and thereafter. The adoption will not have an impact on the Company's financial statements. Effective January 2, 2012, the Company prospectively adopted accounting guidance that was issued to clarify existing fair value measurement guidance as well as enhance fair value disclosures. The additional disclosures required by this guidance include quantitative information about significant unobservable inputs used for Level 3 measurements, qualitative information about the sensitivity of recurring Level 3 measurements, information about any transfers between Level 1 and 2 of the fair value hierarchy, information about when the current use of a non-financial asset is different from the highest and best use, and the hierarchy classification for assets and liabilities whose fair value is disclosed only in the notes to the financial statements. The adoption of this standard did not have a material impact on the Company's financial statements. *Use of Estimates* The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates. *Reclassifications* Certain amounts in the prior years' financial statements have been reclassified to conform to the current-year presentation.

The entire disclosure for the organization, consolidation and basis of presentation of financial statements disclosure, and significant accounting policies of the reporting entity. May be provided in more than one note to the financial statements, as long as users are provided with an understanding of (1) the significant judgments and assumptions made by an enterprise in determining whether it must consolidate a VIE and/or disclose information about its involvement with a VIE, (2) the nature of restrictions on a consolidated VIE's assets reported by an enterprise in its statement of financial position, including the carrying amounts of such assets, (3) the nature of, and changes in, the risks associated with an enterprise's involvement with the VIE, and (4) how an enterprise's involvement with the VIE affects the enterprise's financial position, financial performance, and cash flows. Describes procedure if disclosures are provided in more than one note to the financial statements.

Acquisitions	12 Months Ended
Acquisitions	Mar. 31, 2012
Acquisitions [Abstract]
Acquisitions	2. Acquisitions In fiscal 2012, the Company completed the following four acquisitions with a combined net purchase price of $24,553, using cash on hand. The Company obtained a controlling financial interest in Powertech Batteries (which is a part of Allied Electronics Corporation Limited (Altron)), in South Africa to produce and market batteries for industrial applications. This will serve both reserve power and motive power customers across sub-Saharan Africa, including South Africa. The Company obtained a controlling financial interest in EAS Germany GmBH, to produce large format lithium-ion battery cells with GAIA Akkumulatorenwerke GmbH ("GAIA"), a wholly owned subsidiary of Lithium Technology Corporation ("LTC"). The Company obtained a controlling financial interest in Energy Leader Batteries India Limited in India to serve both reserve and motive power customers in India. The Company has also acquired Industrial Battery Holding S.A., the parent company of EnerSystem, a market leader in the South American motive power and reserve power battery markets, with headquarters in Buenos Aires, Argentina and with manufacturing plants in Argentina and Brazil as well as operations in Chile. The Company is in the process of finalizing purchase accounting for these acquisitions. The Company made initial allocations of the purchase prices at the dates of the acquisitions based on the estimated fair value of the acquired assets and liabilities assumed. The Company obtained this information during due diligence and through other sources. The Company will finalize the estimates of fair value and the allocations of purchase prices will be adjusted during fiscal 2013. The Company acquired intangible assets, in connection with each acquisition, including trademarks, customer relationships, technology and goodwill. Trademarks were initially valued at $2,000, non-compete agreements at $500, customer relationships at $3,400 and technology at $4,265. Customer relationships, non-compete agreements and technology were assigned finite useful lives and amortization is recorded over the economic life of the intangibles. Goodwill relating to these acquisitions was recorded at $10,723. The results of these acquisitions have been included in the Company's results of operations from the dates of their respective acquisitions. Pro forma earnings per share computations have not been presented as these acquisitions are not considered material. In fiscal 2011, the Company made three acquisitions, the most significant of which was the acquisition of the lithium-ion battery business, ABSL Power Solutions Ltd ("ABSL"), which was completed on February 28, 2011. The purchase price paid for these transactions, net of cash received, was $32,200 and was financed using cash on hand. The Company finalized purchase accounting for these acquisitions. The Company acquired intangible assets, in connection with the ABSL acquisition, including trademarks, customer relationships, technology and goodwill. Trademarks were valued at $1,774, customer relationships at $3,547 and technology at $2,741. Customer relationships and technology were assigned finite useful lives and amortization is recorded over the economic life of the intangibles. Goodwill relating to the acquisition of ABSL was recorded at $15,342. In fiscal 2010, the Company made three acquisitions, the most significant of which was the acquisition of the industrial battery businesses of the Swiss company Accu Holding AG, which included the acquisition of the stock of OEB Traction Batteries and the operating assets and liabilities of Oerlikon Stationery Batteries and its Swedish sales subsidiary (all collectively referred to as "Oerlikon") during November 2009. The accounting for the Oerlikon acquisition resulted in the recognition of a bargain purchase gain of $2,919. The total purchase price for these transactions, net of cash received, was $33,242 and was financed using cash on hand. These acquisitions and the investment provide the Company with an additional range of well respected and designed products for use in high integrity applications in telecommunications, utilities, rail, material handling and mining, as well as other sectors. In connection with certain of its acquisitions, the Company formulated restructuring plans for the integration of the acquired businesses. See Note 20 for additional information regarding these plans.

The entire disclosure for a business combination (or series of individually immaterial business combinations) completed during the period, including background, timing, and recognized assets and liabilities. The disclosure may include leverage buyout transactions (as applicable).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Emerging Issues Task Force (EITF)
-Number 88-16
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 141
-Paragraph 51, 52
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 141R
-Appendix F
-Paragraph F4
-Subparagraph e

Reference 4: http://www.xbrl.org/2003/role/presentationRef
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-Name Statement of Financial Accounting Standard (FAS)
-Number 141R
-Paragraph 67-73
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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-SubTopic 30
-Section 50
-Paragraph 1
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Reference 6: http://www.xbrl.org/2003/role/presentationRef
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Property, Plant, And Equipment [Abstract]

Inventories

12 Months Ended

Mar. 31, 2012

Inventories [Abstract]

Inventories

3. Inventories

Net inventories consist of:


	March 31,
	2012		2011
Raw materials	$	100,538	$	92,928
Work-in-process		111,629		100,261
Finished goods		149,607		141,814


Total	$	361,774	$	335,003

Inventory reserves for obsolescence and other estimated losses, mainly relating to finished goods, were $14,831 and $15,052 at March 31, 2012 and 2011, respectively, and have been included in the net amounts shown above.

Property, Plant, And Equipment

12 Months Ended

Mar. 31, 2012

Property, Plant, And Equipment

4. Property, Plant, and Equipment

Property, plant, and equipment consist of:


	March 31,
	2012			2011
Land, buildings, and improvements	$	201,038		$	174,887
Machinery and equipment		511,599			475,818
Construction in progress		29,779			51,662

		742,416			702,367
Less accumulated depreciation		(389,201	)		(357,982	)


Total	$	353,215		$	344,385

Depreciation expense for the fiscal years ended March 31, 2012, 2011 and 2010 totaled $48,532, $43,517, and $44,145, respectively. Interest capitalized in connection with major construction projects amounted to $797, $1,292, and $929 for the fiscal years ended March 31, 2012, 2011 and 2010, respectively.

The entire disclosure for long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale. Examples include land, buildings, machinery and equipment, and other types of furniture and equipment including, but not limited to, office equipment, furniture and fixtures, and computer equipment and software. This disclosure may include property plant and equipment accounting policies and methodology, a schedule of property, plant and equipment gross, additions, deletions, transfers and other changes, depreciation, depletion and amortization expense, net, accumulated depreciation, depletion and amortization expense and useful lives, income statement disclosures, assets held for sale and public utility disclosures.

Goodwill And Other Intangible Assets [Abstract]

Goodwill And Other Intangible Assets

12 Months Ended

Mar. 31, 2012

Goodwill And Other Intangible Assets

5. Goodwill and Other Intangible Assets

Information regarding the Company's other intangible assets are as follows:


	March 31,
	2012							2011
	Gross Amount		Accumulated Amortization			Net Amount		Gross Amount		Accumulated Amortization			Net Amount
Indefinite-lived intangible assets:
Trademarks	$	86,745	$	(953	)	$	85,792	$	83,021	$	(953	)	$	82,068
Finite-lived intangible assets:
Customer relationships		14,330		(2,839	)		11,491		11,064		(1,880	)		9,184
Non-compete		2,602		(1,224	)		1,378		2,117		(954	)		1,163
Patents		5,230		(615	)		4,615		3,402		(210	)		3,192
Trademarks		2,003		(643	)		1,360		3,771		(559	)		3,212
Licenses		2,640		(194	)		2,446		82		(82	)		-


Total	$	113,550	$	(6,468	)	$	107,082	$	103,457	$	(4,638	)	$	98,819

The Company's amortization expense, related to finite-lived intangible assets was $1,828, $876, and $706, for the years ended March 31, 2012, 2011 and 2010, respectively. The expected amortization expense based on the finite-lived intangible assets as of March 31, 2012, is $2,463 in 2013, $2,238 in 2014, $2,124 in 2015, $2,092 in 2016 and $1,966 in 2017.

The changes in the carrying amount of goodwill by business segment are as follows:


	Fiscal year ended March 31, 2012
	Europe			Americas			Asia		Total
Balance at beginning of year	$	177,881		$	143,225		$	22,560	$	343,666
Goodwill acquired during the year		1,250			7,973			1,500		10,723
Adjustments related to the finalization of purchase accounting for prior year acquisitions		374			5			-		379
Foreign currency translation		(7,977	)		(449	)		719		(7,707	)


Balance at end of year	$	171,528		$	150,754		$	24,779	$	347,061


	Fiscal year ended March 31, 2011
	Europe		Americas		Asia		Total
Balance at beginning of year	$	162,641	$	132,915	$	21,709	$	317,265
Goodwill acquired during the year		7,710		7,591		-		15,301
Adjustments related to the finalization of purchase accounting for prior year acquisitions		24		2,250		-		2,274
Foreign currency translation		7,506		469		851		8,826


Balance at end of year	$	177,881	$	143,225	$	22,560	$	343,666

The Company estimated tax-deductible goodwill to be approximately $12,745 and $14,982 as of March 31, 2012 and 2011, respectively.

The entire disclosure for the aggregate amount of goodwill and a description of intangible assets, which may include (a) for amortizable intangible assets (also referred to as finite-lived intangible assets), the carrying amount, the amount of any significant residual value, and the weighted-average amortization period, (b) for intangible assets not subject to amortization (also referred to as indefinite-lived intangible assets), the carrying amount, and (c) the amount of research and development assets acquired and written off in the period, including the line item in the income statement in which the amounts written off are aggregated, if not readily apparent from the income statement. Also discloses (a) for amortizable intangibles assets in total and by major class, the gross carrying amount and accumulated amortization, the total amortization expense for the period, and the estimated aggregate amortization expense for each of the five succeeding fiscal years, (b) for intangible assets not subject to amortization the carrying amount in total and by major class, and (c) for goodwill, in total and for each reportable segment, the changes in the carrying amount of goodwill during the period (including the aggregate amount of goodwill acquired, the aggregate amount of impairment losses recognized, and the amount of goodwill included in the gain (loss) on disposal of a reporting unit). If any part of goodwill has not been allocated to a reportable segment, discloses the unallocated amount and the reasons for not allocating. For each impairment loss recognized related to an intangible asset (excluding goodwill), discloses: (a) a description of the impaired intangible asset and the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method for determining fair value, (c) the caption in the income statement or the statement of activities in which the impairment loss is aggregated, and (d) the segment in which the impaired intangible asset is reported. For each goodwill impairment loss recognized, discloses: (a) a description of the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method of determining the fair value of the associated reporting unit, and (c) if a recognized impairment loss is an estimate not finalized and the reasons why the estimate is not final. May also disclose the nature and amount of any significant adjustments made to a previous estimate of an impairment loss.

Prepaid And Other Current Assets [Abstract]

Prepaid And Other Current Assets

12 Months Ended

Mar. 31, 2012

Prepaid And Other Current Assets

6. Prepaid and Other Current Assets

Prepaid and other current assets consist of the following:


	March 31,
	2012		2011
Prepaid non income taxes	$	23,737	$	22,753
Non-trade receivables		8,247		8,214
Prepaid income taxes		7,716		15,986
Lead hedges		—		9,575
Other		12,693		13,675

Total	$	52,393	$	70,203

Accrued Expenses

12 Months Ended

Mar. 31, 2012

Accrued Expenses [Abstract]

Accrued Expenses

7. Accrued Expenses

Accrued expenses consist of the following:


	March 31,
	2012		2011
Payroll and benefits	$	55,595	$	58,794
Accrued selling expenses		26,269		24,257
Warranty		19,274		16,218
Income taxes payable		16,979		15,591
VAT and other non-income taxes		10,966		11,937
Freight		12,314		10,208
Deferred income		12,057		7,107
Interest rate swaps		3,628		—
Interest		2,040		2,471
Pension and social security		1,696		1,854
Restructuring		1,186		5,323
Other		26,399		30,940

Total	$	188,403	$	184,700

Debt

12 Months Ended

Mar. 31, 2012

Debt [Abstract]

Debt

8. Debt

Summary of Long-Term Debt

The following summarizes the Company's long-term debt:


	March 31,
	2012		2011
3.375% Convertible Notes, net of discount, due 2038	$	148,272	$	141,837
2011 Credit Facility due 2016		79,400		100,000
China Term Loan due 2017		6,034		6,112
India Term Loan due 2017		5,383		-
Other		40		43


		239,129		247,992
Less current portion		2,540		43


Total long-term debt	$	236,589	$	247,949

2011 Senior Secured Revolving Credit Facility

On March 29, 2011, the Company entered into a $350,000 senior secured revolving credit facility ("2011 Credit Facility"). The 2011 Credit Facility matures on March 31, 2016. This facility includes an early termination provision under which the Company is required to meet a liquidity test in February 2015 related to its capacity to meet certain potential obligations related to the Convertible Notes in June 2015. Borrowings under the 2011 Credit Facility bear interest at a floating rate based, at the Company's option, upon (i) LIBOR plus an applicable percentage (currently 1.25%), (ii) the greater of the Federal Funds rate plus 0.50% or the prime rate, or one-month LIBOR plus 1.0%, plus an applicable percentage (currently 0.25%). There are no prepayment penalties on loans under the 2011 Credit Facility. The interest rate as of March 31, 2012 was 1.60%.

Obligations under the 2011 Credit Facility are secured by substantially all of the Company's existing and future acquired assets, including substantially all of the capital stock of the Company's United States subsidiaries that are guarantors under the new credit facility, and 65% of the capital stock of certain of the Company's foreign subsidiaries that are owned by the Company's United States companies.

China Term Loan

During the fourth quarter of fiscal 2011, the Company completed the financing of a 75,000 Chinese Renminbi (RMB) ($11,909) credit facility ("China Term Loan"). This is a six year term loan to provide a portion of the capital requirements for the Company's operations in China. At March 31, 2012, the Company had drawn RMB 38,000 ($6,034). This term loan currently bears interest at a rate of 7.26% per annum, adjusted annually, based on the official Peoples Bank of China Bank Rate and is payable in quarterly installments of RMB 2,000 ($318) commencing in April 2012.

India Term Loan

During the fourth quarter of fiscal 2012, the Company entered into a joint venture with Energy Leader Batteries India Limited in India, where the Company acquired majority ownership. The joint venture had, at March 31, 2012, a syndicated term loan ("India Term Loan") with an outstanding balance of 273,780 Indian Rupee (INR) ($5,383). The India Term Loan bears interest at a rate of 15.1% per annum adjusted every two years based on the prevailing Indian Benchmark Prime Lending Rate ("BPLR") and is payable in equal quarterly installments of 15,000 INR ($295) over five years.

Senior Unsecured 3.375% Convertible Notes

On May 28, 2008, the Company completed a registered offering of $172,500 aggregate principal amount of senior unsecured 3.375% Convertible Notes Due 2038 ("Convertible Notes") (see prospectus and supplemental indenture dated May 28, 2008). The Company received net proceeds of $168,200 after the deduction of commissions and offering expenses. The Company used all of the net proceeds to repay a portion of its then existing 2004 senior secured credit facility.

The Convertible Notes are general senior unsecured obligations and rank equally with the Company's existing and future senior unsecured obligations and are junior to any of the Company's future secured obligations to the extent of the value of the collateral securing such obligations. The Convertible Notes are not guaranteed, and are structurally subordinate in right of payment to, all of the (i) existing and future indebtedness and other liabilities of the Company's subsidiaries and (ii) preferred stock of the Company's subsidiaries to the extent of their respective liquidation preferences.

The Convertible Notes require the semi-annual payment of interest in arrears on June 1 and December 1 of each year beginning December 1, 2008, at 3.375% per annum on the principal amount outstanding. The Convertible Notes will accrete principal beginning on June 1, 2015 and will bear contingent interest, if any, beginning with the six-month interest period commencing on June 1, 2015 under certain circumstances. The Convertible Notes will mature on June 1, 2038. Prior to maturity the holders may convert their Convertible Notes into shares of the Company's common stock at any time after March 1, 2015 or prior to that date under certain circumstances. When issued, the initial conversion rate was 24.6305 shares per $1,000 principal amount of Convertible Notes, which was equivalent to an initial conversion price of $40.60 per share.

At any time after June 6, 2015, the Company may at its option redeem the Convertible Notes, in whole or in part, for cash, at a redemption price equal to 100% of the principal amount of Convertible Notes to be redeemed, plus any accrued and unpaid interest. A holder of Convertible Notes may require the Company to repurchase some or all of the holder's Convertible Notes for cash upon the occurrence of a fundamental change as defined in the indenture and on each of June 1, 2015, 2018, 2023, 2028 and 2033 at a price equal to 100% of the principal amount of the Convertible Notes being repurchased, plus accrued and unpaid interest, if any, in each case. It is the Company's current intent to settle the principal amount of any conversions in cash, and any additional conversion consideration in cash, shares of EnerSys common stock or a combination of cash and shares. The Convertible Notes will mature on June 1, 2038, unless earlier converted, redeemed or repurchased.

If applicable, the Company will pay a make-whole premium on Convertible Notes converted in connection with certain fundamental changes that occur prior to June 6, 2015. The amount of the make-whole premium, if any, will be based on the Company's stock price and the effective date of the fundamental change. The indenture contains a detailed description of how the make-whole premium will be determined and a table showing the make-whole premium that would apply at various stock prices. No make-whole premium would be paid if the price of the Common Stock on the effective date of the fundamental change is less than $29.00. Any make-whole premium will be payable in shares of Common Stock (or the consideration into which the Company's Common Stock has been exchanged in the fundamental change) on the conversion date for the Convertible Notes converted in connection with the fundamental change.

The Convertible Notes were issued in an offering registered under the Securities Act of 1933, as amended (Securities Act).

In accordance with FASB guidance on the accounting for convertible debt instruments that may be settled in cash upon conversion (including partial settlement), the liability and equity components are separated in a manner that will reflect the entity's non-convertible debt borrowing rate when interest expense is recognized in subsequent periods.

The following represents the principal amount of the liability component, the unamortized discount, and the net carrying amount of our Convertible Notes as of March 31, 2012 and 2011, respectively:


	March 31,			March 31,
	2012			2011
Principal	$	172,500		$	172,500
Unamortized discount		(24,228	)		(30,663	)

Net carrying amount	$	148,272		$	141,837

Carrying amount of equity component	$	29,850		$	29,850

As of March 31, 2012, the remaining discount will be amortized over a period of 38 months. The conversion price of the $172,500 in aggregate principal amount of the Convertible Notes is $40.60 per share and the number of shares on which the aggregate consideration to be delivered upon conversion is 4,248,761.

The effective interest rate on the liability component of the Convertible Notes was 8.50%. The amount of interest cost recognized for the amortization of the discount on the liability component of the Convertible Notes was $6,435, $5,917 and $5,439, respectively, for the fiscal years ended March 31, 2012, 2011 and 2010.

As of March 31, 2012 and 2011, the Company had available and undrawn, under all its lines of credit, $377,230 and $356,447, respectively. Included in the March 31, 2012 and 2011 amounts are $95,340 and $95,049, respectively, of uncommitted lines of credit.

The Company paid $8,933, $16,101 and $16,456, net of interest received, for interest during the fiscal years ended March 31, 2012, 2011 and 2010, respectively.

Aggregate maturities of long-term debt (including $24,228 of Convertible Notes discount) are as follows at March 31, 2012:


2013	$	2,540
2014		2,450
2015		2,450
2016		254,350
2017		1,567
Thereafter


	$	263,357

The Company's financing agreements contain various covenants, which, absent prepayment in full of the indebtedness and other obligations, or the receipt of waivers, would limit the Company's ability to conduct certain specified business transactions including incurring debt, mergers, consolidations or similar transactions, buying or selling assets out of the ordinary course of business, engaging in sale and leaseback transactions, paying dividends and certain other actions. The Company is in compliance with all such covenants.

As of March 31, 2012 and 2011, the Company had $9,108 and $1,150, respectively, of standby letters of credit outstanding under the 2011 Credit Facility and other credit arrangements. As of March 31, 2012 and 2011, the Company had no bank guarantees.

Deferred Financing Fees

In fiscal 2011, in connection with the refinancing of the Company's previous credit facility, the Company wrote-off $2,308 of unamortized deferred financing fees associated with the previous Credit Facility, and incurred $3,500 in new deferred financing fees.

Deferred financing fees, net of accumulated amortization totaled $4,634 and $5,912 as of March 31, 2012 and 2011, respectively. Amortization expense, relating to deferred financing fees, included in interest expense was $1,278, $1,861, and $1,724 for the fiscal years ended March 31, 2012, 2011 and 2010, respectively.

The entire disclosure for information about short-term and long-term debt arrangements, which includes amounts of borrowings under each line of credit, note payable, commercial paper issue, bonds indenture, debenture issue, own-share lending arrangements and any other contractual agreement to repay funds, and about the underlying arrangements, rationale for a classification as long-term, including repayment terms, interest rates, collateral provided, restrictions on use of assets and activities, whether or not in compliance with debt covenants, and other matters important to users of the financial statements, such as the effects of refinancing and noncompliance with debt covenants.

Leases

12 Months Ended

Mar. 31, 2012

Leases [Abstract]

Leases

9. Leases

The Company's future minimum lease payments under capital and operating leases that have noncancelable terms in excess of one year at March 31, 2012 are as follows:


	Capital Leases		Operating Leases
2013	$	451	$	18,268
2014		475		13,478
2015		84		10,108
2016		14		6,981
2017		7		5,008
Thereafter		—		3,588


Total minimum lease payments		1,031	$	57,431


Amounts representing interest		101


Net minimum lease payments, including current portion of $409	$	930

Rental expense was $31,619, $28,047, and $26,957 for the fiscal years ended March 31, 2012, 2011 and 2010, respectively. Amortization of capitalized leased assets is included in depreciation expense. Certain operating lease agreements contain renewal or purchase options and/or escalation clauses.

The entire disclosure for lessee entity's leasing arrangements including, but not limited to, all of the following: (a.) The basis on which contingent rental payments are determined, (b.) The existence and terms of renewal or purchase options and escalation clauses, (c.) Restrictions imposed by lease agreements, such as those concerning dividends, additional debt, and further leasing.

Fair Value Of Financial Instruments [Abstract]

Other Liabilities

12 Months Ended

Mar. 31, 2012

Other Liabilities [Abstract]

Other Liabilities

10. Other Liabilities

Other long-term liabilities consist of the following:


	March 31,
	2012		2011
Pension and profit sharing obligation	$	35,804	$	29,297
Warranty		22,793		19,788
Long-term income taxes liabilities		13,520		11,320
Deferred income		6,094		3,839
Interest rate swap liabilities		244		5,847
Other		14,013		6,552


Total	$	92,468	$	76,643

Fair Value Of Financial Instruments

12 Months Ended

Mar. 31, 2012

Fair Value Of Financial Instruments

11. Fair Value Of Financial Instruments

FASB guidance defines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. This guidance includes a fair value hierarchy that is intended to increase consistency and comparability in fair value measurements and related disclosures. The fair value hierarchy is based on inputs to valuation techniques that are used to measure fair value that are either observable or unobservable. Observable inputs reflect assumptions market participants would use in pricing an asset or liability based on market data obtained from independent sources while unobservable inputs reflect a reporting entity's pricing based upon their own market assumptions. The Company uses the following valuation techniques to measure fair value for its financial assets and financial liabilities:


Level 1		Inputs are unadjusted quoted prices in active markets for identical assets or liabilities.

Level 2		Inputs are quoted prices for similar assets or liabilities in an active market, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable and market-corroborated inputs which are derived principally from or corroborated by observable market data.

Level 3		Inputs are derived from valuation techniques in which one or more significant inputs or value drivers are unobservable.

The following tables represent the financial assets and (liabilities), measured at fair value on a recurring basis as of March 31, 2012 and March 31, 2011 and the basis for that measurement:


	Total Fair Value Measurement March 31, 2012			Quoted Price in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)			Significant Unobservable Inputs (Level 3)
Interest rate swap agreements	$	(3,872	)	$	—	$	(3,872	)	$	—
Lead forward contracts		(851	)		—		(851	)		—
Foreign currency forward contracts		782			—		782			—

Total derivatives	$	(3,941	)	$	—	$	(3,941	)	$	—


	Total Fair Value Measurement March 31, 2011			Quoted Price in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)			Significant Unobservable Inputs (Level 3)
Interest rate swap agreements	$	(5,847	)	$	—	$	(5,847	)	$	—
Lead forward contracts		9,575			—		9,575			—
Foreign currency forward contracts		(2,591	)		—		(2,591	)		—

Total derivatives	$	1,137		$	—	$	1,137		$	—

The fair value of interest rate swap agreements are based on observable prices as quoted for receiving the variable three month LIBOR and paying fixed interest rates and, therefore, were classified as Level 2.

The fair value of lead forward contracts are calculated using observable prices for lead as quoted on the London Metal Exchange ("LME") and, therefore, were classified as Level 2.

The fair value for foreign currency forward contracts are based upon current quoted market prices and are classified as Level 2 based on the nature of the underlying market in which these derivatives are traded.

Financial Instruments

The fair value of the Company's cash and cash equivalents, accounts receivable and accounts payable approximate carrying value due to their short maturities.

The fair value of the Company's 2011 Credit Facility, the China Term Loan, the India Term Loan and short-term debt approximate their carrying value, as they are variable rate debt and the current terms are comparable to market terms as of the balance sheet dates.

The Convertible Notes, with a face value of $172,500, were issued when the Company's stock price was trading at $30.19 per share. On March 31, 2012, the Company's stock price closed at $34.65 per share. The Convertible Notes have a conversion option at $40.60 per share, and due to current conditions in the financial markets, the Company's Convertible Notes were trading at 116% of face value on March 31, 2012, and 125% of face value on March 31, 2011. As of March 31, 2012 and 2011, the unamortized discount on the Convertible Notes was $24,228 and $30,663, respectively.

The carrying amounts and estimated fair values of the Company's derivatives and Convertible Notes at March 31, 2012 and 2011 were as follows:


	March 31, 2012						March 31, 2011
	Carrying Amount			Fair Value			Carrying Amount			Fair Value
Financial assets:
Derivatives ⁽¹⁾	$	782		$	782		$	9,575		$	9,575

Financial liabilities:
Convertible Notes	$	148,272	⁽²⁾	$	200,100	⁽³⁾	$	141,837	⁽²⁾	$	215,625	⁽³⁾
Derivatives ⁽¹⁾		4,723			4,723			8,438			8,438

⁽¹⁾	Represents interest rate swap agreements, lead and foreign currency hedges (see Note 12 for asset and liability positions of the interest rate swap agreements, lead and foreign currency hedges at March 31, 2012 and March 31, 2011).

⁽²⁾	The carrying amounts of the Convertible Notes at March 31, 2012 and March 31, 2011 represent the $172,500 principal value, less the unamortized debt discount (see Note 8).

⁽³⁾	The fair value amounts of the Convertible Notes represent the trading values of the Convertible Notes with a principal value of $172,500 at March 31, 2012 and March 31, 2011.

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 44A, 44B
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 107
-Paragraph 15C, 15D
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 107
-Paragraph 15A
-Subparagraph a-d
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 107
-Paragraph 15B
-Subparagraph a, b
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 107
-Paragraph 3, 10, 14, 15
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 157
-Paragraph 32, 33, 34
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 159
-Paragraph 17-22, 27, 28
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19207-110258

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-Name Accounting Standards Codification
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-Name Accounting Standards Codification
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-Name Accounting Standards Codification
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Derivative Financial Instruments [Abstract]

Derivative Financial Instruments

12 Months Ended

Mar. 31, 2012

Derivative Financial Instruments

12. Derivative Financial Instruments

The Company utilizes derivative instruments to reduce its exposure to commodity price, foreign exchange risks and interest rates, under established procedures and controls. The Company does not enter into derivative contracts for speculative purposes. The Company's agreements are with creditworthy financial institutions and the Company anticipates performance by counterparties to these contracts and therefore no material loss is expected.

Derivatives in Cash Flow Hedging Relationships

Lead Hedge Forward Contracts

The Company enters into lead hedge forward contracts to fix the price for a portion of lead purchases. Management considers the lead hedge forward contracts to be effective against changes in the cash flows of the underlying lead purchases based on the criteria under FASB guidance. The vast majority of such contracts are for a period not extending beyond one year and the notional amounts at March 31, 2012 and 2011 were $60.0 million and $63.4 million pounds, respectively.

Foreign Currency Forward Contracts

The Company purchases lead and other commodities in certain countries where the foreign currency exposure is different from the functional currency of that country. The Company uses foreign currency forward contracts to hedge a portion of the Company's foreign currency exposures for lead and other commodities purchases so that gains and losses on these contracts offset changes in the underlying foreign currency denominated exposures. Each contract is for a period not extending beyond one year. As of March 31, 2012 and 2011, the Company had entered into a total of $42,121 and $71,930, respectively, of such contracts.

In the coming twelve months, the Company anticipates that $1,784 of pretax gain relating to lead and foreign currency forward contracts will be reclassified from AOCI as part of cost of goods sold. This amount represents the current unrealized impact of hedging lead and foreign exchange rates, which will change as market rates change in the future, and will ultimately be realized in the income statement as an offset to the corresponding actual changes in lead costs to be realized in connection with the variable lead cost and foreign exchange rates being hedged.

Derivatives not Designated in Hedging Relationships

Interest Rate Swap Agreements

As of March 31, 2012 and March 31, 2011, the Company maintained interest rate swap agreements that converted $85,000 of variable-rate debt to a fixed-rate basis, utilizing the three-month LIBOR, as a floating rate reference. These agreements, which expire between February 2013 and May 2013, no longer qualified for hedge accounting at the end of fiscal 2011 as a result of the refinancing of the Company's previous credit facility. Changes in the fair value of these agreements of $977 in expense during the twelve months of fiscal 2012 have been recorded in the consolidated statements of income in other (income) expense, net. In fiscal 2011, the changes in the fair value of these agreements were recorded in AOCI.

Foreign Currency Forward Contracts

The Company also enters into foreign currency forward contracts to economically hedge foreign currency fluctuations on intercompany loans and foreign currency denominated receivables. These are not designated as hedging instruments. The notional amount of these contracts was $11,410 as of March 31, 2012. Net changes in the fair value of these agreements of $106 in expense during the twelve months of fiscal 2012 have been recorded in the consolidated statements of income in other (income) expense, net.

Presented below in tabular form is information on the location and amounts of derivative fair values in the consolidated balance sheets and derivative gains and losses in the Consolidated Statements of Income:

Fair Value of Derivative Instruments

March 31, 2012 and 2011


	Derivatives and Hedging Activities Designated as Cash Flow Hedges				Derivatives and Hedging Activities Not Designated as Hedging Instruments
	March 31, 2012		March 31, 2011		March 31, 2012		March 31, 2011
Prepaid and other current assets
Lead hedge forward contracts	$	—	$	9,575	$	—	$	—
Foreign currency forward contracts		670		—		112		—
Other assets		30		—		—		—

Total assets	$	700	$	9,575	$	112	$	—

Accrued expenses
Interest rate swap agreements	$	—	$	—	$	3,628	$	—
Lead hedge forward contracts		881		—		—		—
Foreign currency forward contracts		—		2,591		—		—
Other liabilities
Interest rate swap agreements		—		—		244		5,847

Total liabilities	$	881	$	2,591	$	3,872	$	5,847

The Effect of Derivative Instruments on the Consolidated Statements of Income

For the fiscal year ended March 31, 2012


Derivatives Designated as Cash Flow Hedges	Gain (Loss) Recognized in AOCI on Derivative (Effective Portion)			Location of Gain (Loss) Reclassified from AOCI into Income (Effective Portion)	Gain (Loss) Reclassified from AOCI into Income (Effective Portion)

Lead hedge forward contracts	$	(9,731	)	Cost of goods sold	$	(831	)
Foreign currency forward contracts		(152	)	Cost of goods sold		(3,882	)

Total	$	(9,883	)		$	(4,713	)



Derivatives Not Designated as Hedging Instruments	Location of Gain (Loss) Recognized in Income on Derivative	Gain (Loss)
Interest rate swap contracts	Other (income) expense, net	$	(977	)
Foreign currency forward contracts	Other (income) expense, net		(106	)

Total		$	(1,083	)

The Effect of Derivative Instruments on the Consolidated Statements of Income

For the fiscal year ending March 31, 2011


Derivatives in a Cash Flow Hedging Relationship	Gain (Loss) Recognized in AOCI on Derivative (Effective Portion)			Location of Gain (Loss) Reclassified from AOCI into Income (Effective Portion)	Gain (Loss) Reclassified from AOCI into Income (Effective Portion)

Interest rate swap contracts	$	(2,835	)	Interest expense	$	(6,698	)
Lead hedge forward contracts		15,930		Cost of goods sold		6,417
Foreign currency forward contracts		(4,031	)	Cost of goods sold		471

Total	$	9,064			$	190



Derivatives Not Designated as Hedging Instruments	Location of Gain (Loss) Recognized in Income on Derivative	Gain (Loss)
Interest rate swap contracts	Charges related to refinancing	$	(5,847	)

Total		$	(5,847	)

The Effect of Derivative Instruments on the Consolidated Statements of Income

For the fiscal year ending March 31, 2010


Derivatives in a Cash Flow Hedging Relationship	Gain (Loss) Recognized in AOCI on Derivative (Effective Portion)			Location of Gain (Loss) Reclassified from AOCI into Income (Effective Portion)	Gain (Loss) Reclassified from AOCI into Income (Effective Portion)
Interest rate swap contracts	$	(3,141	)	Interest expense	$	(7,059	)
Lead hedge forward contracts		9,844		Cost of goods sold		11,973
Foreign currency forward contracts		2,679		Cost of goods sold		428

Total	$	9,382				$5,342

The entire disclosure for the entity's entire derivative instruments and hedging activities. Describes an entity's risk management strategies, derivatives in hedging activities and non-hedging derivative instruments, the assets, obligations, liabilities, revenues and expenses arising therefrom, and the amounts of and methodologies and assumptions used in determining the amounts of such items.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 45
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 44
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6887037&loc=d3e80784-113994

Reference 4: http://www.xbrl.org/2003/role/presentationRef
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Income Taxes

12 Months Ended

Mar. 31, 2012

Income Taxes [Abstract]

Income Taxes

13. Income Taxes

Income tax expense is composed of the following:


	Fiscal year ended March 31,
	2012			2011			2010
Current:
Federal	$	30,459		$	24,232		$	9,000
State		3,778			2,736			(981	)
Foreign		16,282			14,114			9,957

Total current		50,519			41,082			17,976
Deferred:
Federal		(1,609	)		(1,358	)		4,678
State		(962	)		2,010			852
Foreign		(656	)		(3,716	)		1,445

Total deferred		(3,227	)		(3,064	)		6,975

Income tax expense	$	47,292		$	38,018		$	24,951

Earnings before income taxes consists of the following:


	Fiscal year ended March 31,
	2012		2011		2010
United States	$	87,597	$	57,710	$	37,418
Foreign		103,662		93,734		49,837

Earnings before income taxes	$	191,259	$	151,444	$	87,255

Income taxes paid by the Company for the fiscal years ended March 31, 2012, 2011 and 2010 were $38,482, $41,800 and $22,553, respectively.

The following table sets forth the tax effects of temporary differences that give rise to significant portions of the deferred tax assets and liabilities:


	March 31,
	2012			2011
Deferred tax assets:
Accounts receivable	$	1,111		$	1,304
Inventories		6,707			6,669
Net operating loss carryforwards		71,773			78,236
Accrued liabilities		26,997			22,061
Other assets		10,228			9,200

Gross deferred tax assets		116,816			117,470
Less valuation allowance		(56,359	)		(63,617	)

Total deferred tax assets		60,457			53,853
Deferred tax liabilities:
Property, plant and equipment		30,957			31,945
Other intangible assets		46,628			43,440
Convertible Notes		21,616			20,727
Other liabilities		2,400			4,992

Total deferred tax liabilities		101,601			101,104

Net deferred tax liabilities	$	(41,144	)	$	(47,251	)

The Company has approximately $11,139 in United States federal net operating loss carryforwards, approximately $3,375 of which are limited by Section 382 of the Internal Revenue Code, that begin to expire in the year ending 2023. The Company has approximately $235,000 of net operating loss carryforwards at March 31, 2012 that relate to the Company's foreign subsidiaries. Some of these net operating loss carryforwards have an unlimited life, while others expire at various times over the next 20 years. In addition, the Company also had approximately $45,559 of net operating loss carryforwards for state tax purposes that expire at various times over the next 20 years.

The Company has recorded a valuation allowance against certain federal net operating losses that are limited by Section 382. As of March 31, 2012 and 2011 these valuation allowances were $793 and $5,432, respectively. Of the decrease, $2,477 was recorded as a tax benefit primarily as a result of increasing the ownership in a domestic joint venture, and $2,162 was offset by a corresponding decrease to the net operating loss deferred tax asset due to the statutory limit on net operating loss usage pursuant to Section 382. The Company has also recorded a valuation allowance for net deferred tax assets in certain foreign and state tax jurisdictions, primarily related to net operating loss carryforwards, due to the significant losses incurred in these tax jurisdictions. As of March 31, 2012 and 2011 the valuation allowance associated with certain foreign tax jurisdictions was $53,206 and $55,738, respectively. As of March 31, 2012 and 2011 the valuation allowance associated with the state tax jurisdictions was $2,360 and $2,447, respectively. During the fiscal years ended March 31, 2012 and 2011, the Company recorded tax benefits of $2,940 and $2,498, respectively, due to the utilization of net operating loss carryforwards in certain foreign subsidiaries.

A reconciliation of income taxes at the statutory rate to the income tax provision is as follows:


	Fiscal year ended March 31,
	2012			2011			2010
United States statutory income tax expense (at 35%)	$	66,962		$	53,005		$	30,539
Increase (decrease) resulting from:
State income taxes, net of federal effect		1,592			3,035			(116	)
Nondeductible expenses, domestic manufacturing deduction and other		1,587			(1,848	)		3,799
Effect of foreign operations		(20,028	)		(14,841	)		(9,253	)
Valuation allowance		(2,821	)		(1,333	)		(18	)

Income tax expense	$	47,292		$	38,018		$	24,951

The effective income tax rate was 24.7% in fiscal 2012, compared to 25.1% in fiscal 2011 and 28.6% in fiscal 2010.

At March 31, 2012, the Company has not recorded United States income or foreign withholding taxes on approximately $494,000 of undistributed earnings of foreign subsidiaries that could be subject to taxation if remitted to the United States because the Company currently plans to keep these amounts permanently invested overseas. It is not practical to calculate the income tax expense that would result upon repatriation of these earnings.

The Company recognizes and measures uncertain tax positions taken, or expected to be taken, in a tax return in accordance with FASB guidance on accounting for uncertainty in income taxes.

A reconciliation of the beginning and ending amount of unrecognized tax benefits under FASB guidance is as follows:


March 31, 2009	$	13,305
Increases related to current year tax positions		919
Increases related to prior year tax positions due to foreign currency translation		5
Decreases related to prior year tax position settled		(2,940	)
Lapse of statute of limitations		(539	)

March 31, 2010		10,750
Increases related to current year tax positions		2,896
Increases related to prior year tax positions		324
Increases related to prior year tax positions due to foreign currency translation		122
Decreases related to prior year tax position settled		(3,145	)
Lapse of statute of limitations		(302	)

March 31, 2011		10,645
Increases related to current year tax positions		5,032
Increases related to prior year tax positions		182
Increases related to prior year tax positions due to foreign currency translation		(28	)
Decreases related to prior year tax position settled		—
Lapse of statute of limitations		(2,886	)

March 31, 2012	$	12,945

All of the balance of unrecognized tax benefits at March 31, 2012 and 2011, if recognized, would be included in the Company's consolidated statements of income and have a favorable impact on both the company's statements of income and effective tax rate.

The Company and its subsidiaries file income tax returns in the U.S. federal jurisdiction, and various states and foreign jurisdictions. With few exceptions, the Company is no longer subject to U.S. federal, state and local, or non-U.S. income tax examinations by tax authorities for years before 2006.

The Company anticipates that it is reasonably possible that a portion of the March 31, 2012 balance of the unrecognized tax benefits could be recognized within the next twelve months due to the expiration of the relevant statutes of limitations. An estimate of the range of the adjustments cannot be made at this time.

The Company recognizes tax related interest and penalties in income tax expense in its consolidated statements of income. As of March 31, 2012 and 2011, the Company had an accrual of $575 and $675, respectively, for interest and penalties.

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 08
-Paragraph h
-Article 4

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 109
-Paragraph 136, 172
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 109
-Paragraph 43, 44, 45, 46, 47, 48, 49
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32718-109319

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32639-109319

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(h))
-URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e23780-122690

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32537-109319

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32559-109319

Retirement Plans

12 Months Ended

Mar. 31, 2012

Retirement Plans [Abstract]

Retirement Plans

14. Retirement Plans

Defined Benefit Plans

The Company provides retirement benefits to substantially all eligible salaried and hourly employees. The Company uses a measurement date of March 31 for its pension plans.

Net periodic pension cost for fiscal 2012, 2011, and 2010, includes the following components:


	United States Plans									International Plans
	Fiscal Year Ended March 31,									Fiscal Year Ended March 31,
	2012			2011			2010			2012			2011			2010
Service cost	$	285		$	250		$	224		$	645		$	603		$	621
Interest cost		668			646			635			2,504			2,503			2,520
Expected return on plan assets		(706	)		(624	)		(491	)		(1,787	)		(1,615	)		(1,256	)
Amortization and deferral		238			248			458			32			53			(43	)

Net periodic benefit cost	$	485		$	520		$	826		$	1,394		$	1,544		$	1,842

The following table sets forth a reconciliation of the related benefit obligation, plan assets, and accrued benefit costs related to the pension benefits provided by the Company for those employees covered by defined benefit plans:


	United States Plans						International Plans
	March 31,						March 31,
	2012			2011			2012			2011
Change in projected benefit obligation
Benefit obligation at the beginning of the period	$	11,903		$	10,992		$	48,881		$	46,851
Service cost		285			250			645			603
Interest cost		668			646			2,504			2,503
Benefits paid, inclusive of plan expenses		(615	)		(581	)		(1,709	)		(1,481	)
Plan settlements		—			—			(40	)		—
Plan amendments		—			108			—			817
Plan combinations (including newly material plans)		—			—			—			337
Experience (gain) loss		1,799			488			5,442			(3,366	)
Foreign currency translation adjustment		—			—			(1,828	)		2,617

Benefit obligation at the end of the period	$	14,040		$	11,903		$	53,895		$	48,881


	United States Plans						International Plans
	March 31,						March 31,
	2012			2011			2012			2011
Change in plan assets
Fair value of plan assets at the beginning of the period	$	8,746		$	7,859		$	25,779		$	22,712
Actual return on plan assets		420			1,102			1,555			1,751
Employer contributions		641			366			1,505			1,424
Benefits paid, inclusive of plan expenses		(615	)		(581	)		(1,709	)		(1,481	)
Plan settlements		—			—			(40	)		—
Foreign currency translation adjustments		—			—			(148	)		1,373

Fair value of plan assets at the end of the period	$	9,192		$	8,746		$	26,942		$	25,779

Funded status deficit	$	(4,848	)	$	(3,157	)	$	(26,953	)	$	(23,102	)


	March 31,
	2012			2011
Amounts recognized in the consolidated balance sheets consist of:
Other assets	$	260		$	2,513
Accrued expenses		(1,309	)		(1,369	)
Other liabilities		(30,752	)		(27,403	)

	$	(31,801	)	$	(26,259	)

The following table represents pension components (before tax) and related changes (net of tax) recognized in AOCI for the Company's pension plans for the years ended March 31, 2012, 2011 and 2010:


	March 31,
	2012			2011			2010
Amounts recorded in AOCI before taxes:
Prior service credit (cost)	$	(922	)	$	(1,054	)	$	(132	)
Net gain (loss)		(11,176	)		(3,712	)		(7,344	)

Net amount recognized	$	(12,098	)	$	(4,766	)	$	(7,476	)


	March 31,
	2012			2011			2010
Changes in plan assets and benefit obligations:
New prior service cost	$	—		$	905		$	—
Net loss /(gain) arising during the year		7,757			(3,505	)		753
Effect of exchange rates on amounts included in AOCI		(176	)		151			40
Amounts recognized as a component of net periodic benefit costs:
Amortization or curtailment recognition of prior service credit /(cost)		(83	)		(62	)		(142	)
Amortization or settlement recognition of net gain/(loss)		(187	)		(250	)		(333	)

Total recognized in other comprehensive income	$	7,311		$	(2,761	)	$	318

The amounts included in AOCI as of March 31, 2012 that are expected to be recognized as components of net periodic pension cost during the fiscal year ended March 31, 2013 are as follows:


Net loss	$	(81	)
Net prior service cost		(534	)

Net amount expected to be recognized	$	(615	)

The accumulated benefit obligation related to all defined benefit pension plans and information related to unfunded and underfunded defined benefit pension plans at the end of each year follows:


	United States Plans				International Plans
	March 31,				March 31,
	2012		2011		2012		2011
All defined benefit plans:
Accumulated benefit obligation	$	14,040	$	11,903	$	50,416	$	46,225
Unfunded defined benefit plans:
Projected benefit obligation		—		—		26,892		25,533
Accumulated benefit obligation		—		—		25,508		24,413
Defined benefit plans with an accumulated benefit obligation in excess of the fair value of plan assets:
Projected benefit obligation		14,040		11,903		28,003		25,560
Accumulated benefit obligation		14,040		11,903		26,445		24,440
Fair value of plan assets		9,192		8,746		789		—

Assumptions

Significant assumptions used to determine the net periodic benefit cost for the US and International plans were as follows:


	United States Plans									International Plans
	March 31,									March 31,
	2012			2011			2010			2012			2011			2010
Discount rate		5.7	%		6.0	%		6.5	%		4.0-5.5	%		4.3-6.0	%		3.8-6.0	%
Expected return on plan assets		8.0			8.0			8.0			5.5-7.0			5.5-7.0			5.5-7.0
Rate of compensation increase		N/A			N/A			N/A			2.0-4.0			2.0-3.5			2.0-3.5

Significant assumptions used to determine the projected benefit obligations for the US and International plans were as follows:


	United States Plans						International Plans
	March 31,						March 31,
	2012			2011			2012			2011
Discount rate		4.8	%		5.7	%		2.5-5.5	%		4.0-5.5	%
Expected return on plan assets		8.0			8.0			5.5-7.0			5.5-7.0
Rate of compensation increase		N/A			N/A			2.0-4.0			2.0-4.0

N/A = not applicable

The United States plans do not include compensation in the formula for determining the pension benefit as it is based solely on years of service.

The expected long-term rate of return for the Company's pension plan assets is based upon the target asset allocation and is determined using forward looking assumptions in the context of historical returns and volatilities for each asset class, as well as correlations among asset classes. The Company evaluates the rate of return assumptions for each of its plans on an annual basis.

Pension Plan Investment Strategy

The Company's investment policy emphasizes a balanced approach to investing in securities of high quality and ready marketability. Investment flexibility is encouraged so as not to exclude opportunities available through a diversified investment strategy.

Equity investments are maintained within a target range of 50%-70% of the total portfolio market value. Investments in debt securities include issues of various maturities, and the average quality rating of bonds should be investment grade with a minimum quality rating of "B" at the time of purchase.

The Company periodically reviews the asset allocation of its portfolio. The proportion committed to equities, debt securities and cash and cash equivalents is a function of the values available in each category and risk considerations. The plan's overall return will be compared to and expected to meet or exceed established benchmark funds and returns over a three to five year period.

The objectives of the Company's investment strategies are: (a) the achievement of a reasonable long-term rate of total return consistent with an emphasis on preservation of capital and purchasing power, (b) stability of annual returns through a portfolio risk level, which is appropriate to conservative accounts, and (c) reflective of the Company's willingness to forgo significantly above-average rewards in order to minimize above-average risks. These objectives may not be met each year but should be attained over a reasonable period of time.

In connection with a past acquisition, the Company had assumed defined benefit plans in Germany and France. These plans have no assets, while their benefit obligations were $22,874 and $21,706 as of March 31, 2012 and 2011, respectively. Other salary and hourly employees are provided benefits in accordance with governmental regulatory requirements.

The following table represents our pension plan investments measured at fair value as of March 31, 2012 and 2011 and the basis for that measurement:


	March 31, 2012
	United States Plans								International Plans
	Total Fair Value Measurement		Quoted Price In Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total Fair Value Measurement		Quoted Price In Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Asset Category:
Cash and Cash Equivalents	$	868	$	868	$	—	$	—	$	—	$	—	$	—	$	—
Equity Securities
US^(a)		5,067		5,067		—		—		2,742		2,742		—		—
International^(b)		837		837		—		—		14,728		14,728		—		—
Fixed Income^(c)		2,420		2,420		—		—		9,472		9,472		—		—

Total	$	9,192	$	9,192	$	—	$	—	$	26,942	$	26,942	$	—	$	—


	March 31, 2011
	United States Plans								International Plans
	Total Fair Value Measurement		Quoted Price In Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total Fair Value Measurement		Quoted Price In Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Asset Category:
Cash and Cash Equivalents	$	528	$	528	$	—	$	—	$	—	$	—	$	—	$	—
Equity Securities
US^(a)		4,839		4,839		—		—		2,521		2,521		—		—
International^(b)		840		840		—		—		13,600		13,600		—		—
Fixed Income^(c)		2,539		2,539		—		—		9,658		9,658		—		—

Total	$	8,746	$	8,746	$	—	$	—	$	25,779	$	25,779	$	—	$	—

The fair values presented above were determined based on valuation techniques categorized as follows:

•

Level one: The use of unadjusted quoted prices in active markets for identical instruments.

•

Level two: The use of quoted prices for similar instruments in active markets or quoted prices for identical or similar instruments in markets that are not active or other inputs that are observable in the market or can be corroborated by observable market data.

•

Level three: The use of significant unobservable inputs and that typically require the use of management's estimates of assumptions that market participants would use in pricing.

(a)

US equities include companies that are well diversified by industry sector and equity style (i.e., growth and value strategies). Active and passive management strategies are employed. Investments are primarily in large capitalization stocks and, to a lesser extent, mid- and small-cap stocks.

(b)

International equities are invested in companies that are traded on exchanges outside the U.S. and are well diversified by industry sector, country and equity style. Active and passive strategies are employed. The vast majority of the investments are made in companies in developed markets with a small percentage in emerging markets.

(c)

Fixed income consists primarily of investment grade bonds from diversified industries.

The Company expects to make cash contributions of approximately $2,571 to its pension plans in fiscal year 2013.

Estimated future benefit payments under the Company's pension plans are as follows:


	Pension Benefits
2013	$	2,173
2014		2,319
2015		2,445
2016		2,674
2017		2,993
Years 2018-2022		17,281

Defined Contribution Plan

Effective January 1, 2004, the Company amended its Defined Contribution Plan (the "401(k) Plan"). The amended 401(k) Plan covers substantially all U.S. salaried and hourly employees except those covered by a union plan. All eligible employees of the amended 401(k) Plan receive a matching contribution of 100% of the first 4% of wages contributed and 50% of the next 2% of wages contributed for a total match of up to 5% by the Company.

Effective February 1, 2009, the Company amended the EnerSys United Kingdom Pension Scheme ("Amended U.K. Plan") that covers substantially all United Kingdom employees, both direct and salaried so that all members with defined benefit plan benefits at that date would be provided with defined contribution plan benefits for future service. The Company pays contributions to fund any accrued liabilities in excess of the assets in the defined benefit section of the Amended U.K. Plan as necessary. Active members of the Amended U.K. Plan as of February 1, 2009 receive a matching contribution from the Company up to 4% of Pensionable Salary and an enhanced Company contribution in excess of this in line with the rules of the plan. New eligible employees of the Amended U.K. Plan receive a matching contribution from the Company up to 5% of pensionable salary, at various rates as provided by the plan.

Employer expenses for the 401(k) plan and the Amended U.K. Plan for the fiscal years ended March 31, 2012, 2011 and 2010 were $5,146, $5,025 and $3,909, respectively.

The entire disclosure for pension and other postretirement benefits.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5
-Subparagraph a
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5
-Subparagraph b
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5
-Subparagraph h
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5
-Subparagraph q
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 8
-Subparagraph m
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 106
-Paragraph 518
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 87
-Paragraph 264
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Emerging Issues Task Force (EITF)
-Number 03-2
-Paragraph 8
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Principles Board Opinion (APB)
-Number 30
-Paragraph 26
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Staff Position (FSP)
-Number FAS106-2
-Paragraph 20, 21, 22
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 158
-Paragraph 7, 21, 22
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5, 6, 7, 8
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Implementation Guide (Q and A)
-Number FAS88
-Paragraph 63
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-URI http://asc.fasb.org/topic&trid=2235017

Stockholders' Equity

12 Months Ended

Mar. 31, 2012

Stockholders' Equity [Abstract]

Stockholders' Equity

15. Stockholders' Equity

Preferred Stock and Common Stock

The Company's certificate of incorporation authorizes the issuance of up to 1,000,000 shares of preferred stock, par value $0.01 per share ("Preferred Stock"). At March 31, 2012 and 2011, no shares of Preferred Stock were issued or outstanding. The Board of Directors of the Company has the authority to specify the terms of any Preferred Stock at the time of issuance.

The following demonstrates the change in the number of shares of common stock outstanding during fiscal 2012:


Shares outstanding as of March 31, 2011	50,034,353
Repurchase of common shares	(2,646,885	)
Shares issued as part of equity-based compensation plans, net of equity awards surrendered for option price and taxes	412,661

Shares outstanding as of March 31, 2012	47,800,129

Treasury Stock

In fiscal 2012, the Company purchased 2,646,885 shares of its common stock for $58,383 from institutional shareholders and recorded the same as treasury stock. Treasury stock as of March 31, 2012 and 2011 was $78,183 and $19,800, respectively.

Accumulated Other Comprehensive Income

The components of accumulated other comprehensive income are as follows:


	Beginning Balance			Before-Tax Amount			Tax Benefit (Expense)			Net-of-Tax Amount			Ending Balance
March 31, 2012
Pension funded status adjustment	$	(3,512	)	$	(7,311	)	$	1,841		$	(5,470	)	$	(8,982	)
Unrealized gain (loss) on derivative instruments		4,436			(5,170	)		1,909			(3,261	)		1,175
Foreign currency translation adjustment		114,256			(32,356	)		—			(32,356	)		81,900

Accumulated other comprehensive income	$	115,180		$	(44,837	)	$	3,750		$	(41,087	)	$	74,093

March 31, 2011
Pension funded status adjustment	$	(5,479	)	$	2,761		$	(794	)	$	1,967		$	(3,512	)
Unrealized gain (loss) on derivative instruments		(5,034	)		14,721			(5,251	)		9,470			4,436
Foreign currency translation adjustment		77,717			36,539			—			36,539			114,256

Accumulated other comprehensive income	$	67,204		$	54,021		$	(6,045	)	$	47,976		$	115,180

March 31, 2010
Pension funded status adjustment	$	(4,794	)	$	(318	)	$	(367	)	$	(685	)	$	(5,479	)
Unrealized gain (loss) on derivative instruments		(7,660	)		4,047			(1,421	)		2,626			(5,034	)
Foreign currency translation adjustment		46,509			31,208			—			31,208			77,717

Accumulated other comprehensive income	$	34,055		$	34,937		$	(1,788	)	$	33,149		$	67,204

The entire disclosure for shareholders' equity, comprised of portions attributable to the parent entity and noncontrolling interest, if any, including other comprehensive income (as applicable). Including, but not limited to: (1) balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings; (2) accumulated balance for each classification of other comprehensive income and total amount of comprehensive income; (3) amount and nature of changes in separate accounts, including the number of shares authorized and outstanding, number of shares issued upon exercise and conversion, and for other comprehensive income, the adjustments for reclassifications to net income; (4) rights and privileges of each class of stock authorized; (5) basis of treasury stock, if other than cost, and amounts paid and accounting treatment for treasury stock purchased significantly in excess of market; (6) dividends paid or payable per share and in the aggregate for each class of stock for each period presented; (7) dividend restrictions and accumulated preferred dividends in arrears (in aggregate and per share amount); (8) retained earnings appropriations or restrictions, such as dividend restrictions; (9) impact of change in accounting principle, initial adoption of new accounting principle and correction of an error in previously issued financial statements; (10) shares held in trust for Employee Stock Ownership Plan (ESOP); (11) deferred compensation related to issuance of capital stock; (12) note received for issuance of stock; (13) unamortized discount on shares; (14) description, terms, and number of warrants or rights outstanding; (15) shares under subscription and subscription receivables, effective date of new retained earnings after quasi-reorganization and deficit eliminated by quasi-reorganization and, for a period of at least ten years after the effective date, the point in time from which the new retained dates; and (16) retroactive effective of subsequent change in capital structure.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Principles Board Opinion (APB)
-Number 12
-Paragraph 10
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Article 3

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 4
-Section 08
-Paragraph d

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 43
-Chapter 1
-Section B
-Paragraph 7, 11A
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 129
-Paragraph 2, 3, 4, 5, 6, 7, 8
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 08
-Article 4

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 5
-Paragraph 15
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 29, 30, 31
-Article 5

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 4
-Section E

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 4
-Section C

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=6959260&loc=d3e187085-122770

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 13: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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Reference 14: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21484-112644

Reference 15: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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Reference 16: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 17: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 235
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-Paragraph 1
-Subparagraph (SX 210.4-08.(d),(e))
-URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e23780-122690

Reference 18: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21506-112644

Reference 19: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
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-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6405834&loc=d3e23285-112656

Reference 20: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB TOPIC 4.E)
-URI http://asc.fasb.org/extlink&oid=6228006&loc=d3e74512-122707

Reference 21: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Preferred Stock
-URI http://asc.fasb.org/extlink&oid=6521494

Reference 22: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.29-31)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 23: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SAB TOPIC 4.C)
-URI http://asc.fasb.org/extlink&oid=6959260&loc=d3e187143-122770

Secondary Offerings Of Common Shares	12 Months Ended
Secondary Offerings Of Common Shares	Mar. 31, 2012
Secondary Offerings Of Common Shares [Abstract]
Secondary Offerings Of Common Shares	16. Secondary Offerings of Common Shares In fiscal 2011 and 2010, certain of the Company's stockholders sold 2,845,869 and 3,200,000 shares of the Company's common stock pursuant to an effective shelf registration statement filed with the Securities and Exchange Commission on May 19, 2008. The offered shares were sold by those stockholders of the Company, including affiliates of Metalmark Capital LLC and certain other institutional stockholders. The Company did not receive any proceeds from the common stock offerings; however, under the terms of its securityholder agreement, the Company did incur fees related to the offerings in fiscal 2011 and fiscal 2010 of $615 and $150, respectively. There were no secondary offerings in fiscal 2012.

Stock-Based Compensation

12 Months Ended

Mar. 31, 2012

Stock-Based Compensation [Abstract]

Stock-Based Compensation

17. Stock-Based Compensation

As of March 31, 2012, the Company maintains the EnerSys 2010 Equity Incentive Plan ("2010 EIP"). The 2010 EIP reserves 3,177,477 shares of common stock for the grant of various classes of nonqualified stock options, restricted stock units, market share units and other forms of equity-based compensation. Shares subject to any awards that expire without being exercised or that are forfeited or settled in cash shall again be available for future grants of awards under the 2010 EIP. Shares subject to awards that have been retained by the Company in payment or satisfaction of the exercise price and any applicable tax withholding obligation of an award shall not count against the limit described above, and only the number of shares delivered in the settlement of stock appreciation rights shall count against the limit.

At March 31, 2012, 2,872,490 shares are available for future grants. The Company's management equity incentive plans are intended to provide an incentive to employees and non-employee directors of the Company to remain in the service of the Company and to increase their interest in the success of the Company in order to promote the long-term interests of the Company. The plans seek to promote the highest level of performance by providing an economic interest in the long-term performance of the Company. The Company settles employee share-based compensation awards with newly issued shares.

Stock Options

Non-qualified stock options have been granted to employees under the equity incentive plans at prices not less than the fair market value of the shares on the dates the options were granted. Options issued in fiscal 2010 vest over a three-year or six-month period. Options become exercisable in equal installments over the vesting period. No non-qualified stock options were granted in fiscal 2012 or 2011. Options generally expire in 10 years, however options vesting in six months expire in 3 1/2 years.

The weighted average fair value of options granted in fiscal 2010 were $8.35 and $5.15, and were determined using the following assumptions:


	2010			2010
	10 Year Options			3.5 Year Options
Exercise price	$	16.20		$	16.24
Risk-free interest rate		2.01	%		0.93	%
Dividend yield		0	%		0	%
Expected life		5years			2years
Expected volatility		56.6	%		56.6	%
Weighted average fair value	$	8.35		$	5.15

For fiscal 2012, 2011 and 2010, the Company recognized $1,092 ($822 net of taxes), $2,333 ($1,844 net of taxes) and $2,993 ($2,095 net of taxes), respectively, of stock-based compensation expense associated with the stock option grants.

The following table summarizes the Company's stock option activity in the years indicated:


	Number of Options			Weighted Average Remaining Contract Term (Years)		Weighted Average Exercise Price		Aggregate Intrinsic Value
Options outstanding as of March 31, 2009		2,643,175			4.2	$	16.70	$	1,752
Granted		539,506					16.21		—
Exercised		(667,862	)				12.22		7,125
Canceled		(83,586	)				21.43		522

Options outstanding as of March 31, 2010		2,431,233			4.0	$	17.69	$	19,191
Exercised		(1,415,391	)				15.34		18,482
Canceled		(155,063	)				29.32		9

Options outstanding as of March 31, 2011		860,779			6.2	$	19.52	$	17,129
Exercised		(227,116	)				15.82		3,691

Options outstanding as of March 31, 2012		633,663			6.1	$	20.85	$	8,879

Options exercisable as of March 31, 2012		523,626			5.9	$	21.82	$	6,826

Options expected to vest after March 31, 2012		110,037			7.1	$	16.20	$	2,053

The following table summarizes information regarding stock options outstanding and exercisable at March 31, 2012:


	Options Outstanding						Options Exercisable
Range of Exercise Prices	Number of Options		Weighted Average Remaining Contractual Life		Weighted Average Exercise Price		Number of Options		Weighted Average Exercise Price
$10.01-15.00		65,954		3.1	$	14.12		65,954	$	14.12
$15.01-20.00		361,661		6.6		16.75		251,624		16.99
Over $20.00		206,048		6.1		30.19		206,048		30.19


		633,663		6.1	$	20.85		523,626	$	21.82

A summary of the status of the Company's non-vested options as of March 31, 2012, and changes during the year ended March 31, 2012, is presented below:


	Number of Options			Weighted Average Grant-Date Fair Value
Nonvested at March 31, 2011		357,903		$	8.70
Vested		(247,866	)		9.06


Nonvested at March 31, 2012		110,037		$	7.87

Restricted Stock Units and Market Share Units

In fiscal 2012, the Company granted to non-employee directors 35,632 deferred restricted stock units at the market price of $22.45 per restricted stock unit at the date of grant. The fiscal 2012 non-employee director awards vested immediately upon the date of grant and the payment of shares of common stock under this grant are payable upon such director's termination of service as a director. In fiscal 2011, the Company granted to non-employee directors 21,248 restricted stock units at the market price of $22.59 per restricted stock unit at the date of grant. The fiscal 2011 non-employee director awards vested thirteen months following the date of grant.

In fiscal 2012, the Company granted to management and other key employees 95,026 restricted stock units at the market price on that date of $35.79 per share and 224,397 market share units at the fair market value on that date of $48.36 per share. Restricted stock units are granted at the market price of the Company's common stock on the date of grant and vest and are settled in common stock 25% per year over a four-year period from the date of grant. Also, in fiscal 2012, the Company granted 9,340 restricted stock units, at various fair values, under deferred compensation plans.

Market share units are granted at fair value on the date of grant and vest and are settled in common stock on the third anniversary of the date of grant. Market share units are converted into between zero and two shares of common stock for each unit granted at the end of a three-year performance cycle. The conversion ratio is calculated by dividing the average closing share price of the Company's common stock during the ninety calendar days immediately preceding the vesting date by the average closing share price of the Company's common stock during the ninety calendar days immediately preceding the grant date, with the resulting quotient capped at two. This quotient is then multiplied by the number of market share units granted to yield the number of shares of common stock to be delivered on the vesting date. The fair value of the market share units granted in fiscal 2012 was estimated at the date of grant using a binomial lattice model with the following assumptions: a risk-free interest rate of 0.93%, dividend yield of zero, time to maturity of 3 years and expected volatility of 45.5%.

In fiscal 2011, the Company granted to management and other key employees 291,701 restricted stock units at the market price on that date of $25.67 per share and 124,091 market share units at the fair market value on that date of $34.45 per share. These restricted stock units are granted at the fair market value of the Company's common stock on the date of grant and vest 25% per year over a four-year period from the date of grant. The fair value of the market share units granted in fiscal 2011 was estimated at the date of grant using a binomial lattice model with the following assumptions: a risk-free interest rate of 1.30%, dividend yield of zero, time to maturity of 3 years and expected volatility of 43.0%.

A summary of the changes in restricted stock units and market share units awarded to employees and directors that were outstanding under the Company's equity compensation plans during fiscal 2012 is presented below:


	Restricted Stock Units (RSU) / Market Share Units (MSU)
	Number of RSU and MSU			Weighted Average Grant Date Fair Value

Non-vested awards as of March 31, 2011		865,392		$	23.97
Granted		364,395			40.76
Vested		(259,151	)		22.28
Canceled		(6,833	)		11.49

Non-vested awards as of March 31, 2012		963,803		$	30.84

The Company recognized equity-based compensation expense related to the vesting of restricted stock units and market share units of approximately $10,493, with a related tax benefit of $2,599 for fiscal 2012, $6,723, with a related tax benefit of $1,659 for fiscal 2011, and $3,968, with a related tax benefit of $1,190 for fiscal 2010.

All Award Plans

As of March 31, 2012, unrecognized compensation expense associated with the non-vested incentive awards outstanding was $18,451 and is expected to be recognized over a weighted average period of nineteen months.

The entire disclosure for compensation-related costs for equity-based compensation, which may include disclosure of policies, compensation plan details, allocation of equity compensation, incentive distributions, equity-based arrangements to obtain goods and services, deferred compensation arrangements, employee stock ownership plan details and employee stock purchase plan details.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 123R
-Paragraph 64, 65, A240
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Statement of Position (SOP)
-Number 93-6
-Paragraph 53
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 14

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 50
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6406099&loc=d3e25284-112666

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5047-113901

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
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-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5444-113901

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 40
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6418621&loc=d3e17540-113929

Earnings Per Share

12 Months Ended

Mar. 31, 2012

Earnings Per Share [Abstract]

Earnings Per Share

18. Earnings Per Share

The following table sets forth the reconciliation from basic to diluted average common shares and the calculations of net earnings per common share.


	March 31,
	2012		2011		2010

Net earnings attributable to EnerSys stockholders	$	144,003	$	113,426	$	62,304


Average common shares:
Basic (weighted-average outstanding shares)		48,748,205		49,376,132		48,122,207
Dilutive potential common shares from exercise and lapse of equity awards, net of shares assumed reacquired		467,830		668,114		711,888


Diluted (weighted-average outstanding shares)		49,216,035		50,044,246		48,834,095


Basic earnings per common share attributable to EnerSys stockholders	$	2.95	$	2.30	$	1.29


Diluted earnings per common share attributable to EnerSys stockholders	$	2.93	$	2.27	$	1.28


Anti-dilutive equity awards not included in weighted average common shares — diluted		221,097		—		383,696

The aggregate number of shares that the Company could be obligated to issue upon conversion of its $172,500, Convertible Notes which the Company issued in May 2008, is approximately 4,248,761. It is the Company's current intent to settle the principal amount of any conversions in cash, and any additional conversion consideration in cash, shares of EnerSys common stock or a combination of cash and shares. No contingent shares were included in diluted shares outstanding during fiscal 2012, 2011 and 2010, as the specified conversion price exceeded the average market price of the Company's common stock, and the inclusion of contingent shares would have been anti-dilutive.

Commitments, Contingencies And Litigation	12 Months Ended
Commitments, Contingencies And Litigation	Mar. 31, 2012
Commitments, Contingencies And Litigation [Abstract]
Commitments, Contingencies And Litigation	19. Commitments, Contingencies and Litigation Litigation and Other Legal Matters The Company is involved in litigation incidental to the conduct of its business, the results of which, in the opinion of management, are not likely to be material to the Company's financial condition, results of operations, or cash flows. In fiscal 2009, the Court of Commerce in Lyon, France ruled that the Company's French subsidiary, EnerSys Sarl, which was acquired by the Company in 2002, was partially responsible for a 1999 fire in a French hotel under construction. The Company's portion of damages was assessed at €2,700 or $4,200 which was duly recorded and paid by the Company, but the ruling was appealed. In a subsequent ruling by the Court of Appeal of Lyon, France, the portion of damages was reduced, entitling the Company to a refund of the monies paid of €671 or $900 which has been recorded and collected in the second quarter of fiscal 2012. The Company further appealed the ruling to the French Supreme Court, which on March 14, 2012, ruled in the Company's favor and ordered the case back to the Court of Appeal of Lyon to further review certain aspects of the original decision in the case, including the assessment of damages. Environmental Issues As a result of its operations, the Company is subject to various federal, state and local, as well as international environmental laws and regulations and is exposed to the costs and risks of registering, handling, processing, storing, transporting, and disposing of hazardous substances, especially lead and acid. The Company's operations are also subject to federal, state, local and international occupational safety and health regulations, including laws and regulations relating to exposure to lead in the workplace. The Company is responsible for certain cleanup obligations at the former Yuasa battery facility in Sumter, South Carolina that predates its ownership of this facility. This manufacturing facility was closed in 2001 and is separate from the Company's current metal fabrication facility in Sumter. The Company has established a reserve for this facility. As of March 31, 2012 and 2011, the reserves related to this facility totaled $2,995 and $3,279, respectively. Based on current information, the Company's management believes these reserves are adequate to satisfy the Company's environmental liabilities at this facility. In September 2011, the Company's facility in Jiangsu Province, China, was closed by government authorities for an environmental review. After completion of the review, the government authorities allowed the plant to reopen in November 2011 on a conditional basis, with the understanding that the Company would work with the assistance of the government agencies, to relocate to a more preferable location. Collective Bargaining At March 31, 2012, the Company had approximately 9,200 employees. Of these employees, approximately 40% were covered by collective bargaining agreements. The average term of these agreements is two years, with the longest term being four years. These agreements expire over the period from calendar years 2012 to 2014. Lead Contracts To stabilize its costs, the Company has entered into contracts with financial institutions to fix the price of lead. The vast majority of such contracts are for a period not extending beyond one year. Under these contracts, at March 31, 2012 and 2011, the Company hedged the price to purchase approximately 60.0 million and 63.4 million pounds of lead, respectively, for a total purchase price of $56,610 and $68,212, respectively. Foreign Currency Forward Contracts The Company quantifies and monitors its global foreign currency exposures. On a selective basis the Company will enter into foreign currency forward and option contracts to reduce the volatility from currency movements that affect the Company. The maturity period of these contracts is less than one year. The Company's largest exposure is from the purchase and conversion of U.S. dollar based lead costs into local currencies in Europe. Additionally, the Company has currency exposures from intercompany and third party trade transactions. To hedge these exposures, the Company has entered into a total of $53,531 and $82,829, respectively, of foreign currency forward contracts with financial institutions as of March 31, 2012 and 2011. Interest Rate Swap Agreements The Company is exposed to changes in variable U.S. interest rates on borrowings under its credit agreements. On a selective basis, from time to time, the Company enters into interest rate swap agreements to reduce the negative impact that increases in interest rates could have on its outstanding variable rate debt. At March 31, 2012 and March 31, 2011, such agreements, which expire between February 2013 and May 2013, converted $85,000 of variable-rate debt to a fixed-rate basis, utilizing the three-month LIBOR, as a floating rate reference. Fluctuations in LIBOR and fixed rates affect both the Company's net financial investment position and the amount of cash to be paid or received under these agreements.

The entire disclosure for commitments and contingencies.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Interpretation (FIN)
-Number 14
-Paragraph 3
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 5
-Paragraph 9, 10, 11, 12
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.25)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6952336&loc=d3e14435-108349

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
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-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=6398077&loc=d3e12565-110249

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-Publisher FASB
-Name Accounting Standards Codification
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-Paragraph 2
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
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-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6449706&loc=d3e16207-108621

Restructuring Plans

12 Months Ended

Mar. 31, 2012

Restructuring Plans [Abstract]

Restructuring Plans

20. Restructuring Plans

The Company has acquisition related restructuring plans and non-acquisition related restructuring plans and bases its restructuring accounting and disclosures on the applicable accounting guidance. As a result, charges to net earnings were made in the periods in which restructuring plan liabilities were incurred.

Acquisition related restructuring plan

In fiscal 2010, the Company acquired the stock of OEB Traction Batteries and certain operating assets and liabilities of the reserve power battery business of Accu Holding AG and its Swedish sales subsidiary (all collectively referred to as "Oerlikon"). The Company completed the process of closing the two manufacturing facilities of Oerlikon during the third quarter of fiscal 2011, which resulted in the reduction of approximately 100 employees. The Company recorded restructuring charges related to this plan of $4,526 in fiscal 2010 through fiscal 2012. This plan has been completed as of March 31, 2012.

A roll-forward of the acquisition related restructuring reserve is as follows:


	Employee Severance			Plant Closure and Other			Total

Balance at March 31, 2009	$	—		$	—		$	—
Accrued		1,269			—			1,269
Costs incurred		—			—			—
Foreign currency impact and other		23			—			23

Balance at March 31, 2010	$	1,292		$	—		$	1,292
Accrued		108			2,438			2,546
Costs incurred		(1,107	)		(2,313	)		(3,420	)
Foreign currency impact and other		(36	)		21			(15	)

Balance at March 31, 2011	$	257		$	146		$	403
Accrued		81			630			711
Costs incurred		(338	)		(776	)		(1,114	)


Balance at March 31, 2012	$	—		$	—		$	—

Non-acquisition related restructuring plans

In February and May 2009, the Company announced a plan to restructure certain of its European and American operations, which resulted in a reduction of approximately 470 employees upon completion across its operations. These actions were primarily in Europe and included charges for employee-related severance payments and asset impairments, the most significant of which was the closure of its leased Italian manufacturing facility and the opening of a new Italian distribution center. The Company recorded restructuring charges of $31,894 in fiscal 2009 through fiscal 2011, with $105 of additional charges offset by a favorable accrual adjustment of $246 during fiscal 2012. The Company incurred $2,270 of costs against the accrual during fiscal 2012. This plan has been completed as of March 31, 2012.

During fiscal 2011, the Company announced a further restructuring of its European operations, which will result in the reduction of approximately 60 employees upon completion across its operations. The Company estimates that the total charges for these actions will amount to approximately $5,200, primarily from cash expenses for employee severance-related payments and site closure costs. Based on commitments incurred to date, the Company recorded restructuring charges of $3,830 in fiscal 2011, with $1,783 of additional charges, offset by a favorable accrual adjustment of $435 related to the fiscal 2011 plan recorded in fiscal 2012. The Company incurred $1,316 of costs against the accrual during fiscal 2011, with an additional $3,263 of costs incurred during fiscal 2012. As of March 31, 2012, the reserve balance associated with these actions is $556. The Company does not expect to be committed to significant additional restructuring charges in fiscal 2013 related to these actions.

During fiscal 2012, the Company announced restructuring plans related to its operations in Europe, primarily consisting of the transfer of manufacturing of select products between certain of its manufacturing operations and restructuring of its selling, general and administrative operations, which is expected to result in the reduction of approximately 80 employees upon completion. The Company estimates that the total charges for these actions will amount to approximately $4,200, primarily from cash expenses for employee severance-related payments. During fiscal 2012, the Company recorded restructuring charges of $3,070 and incurred $2,433 of costs against the accrual. As of March 31, 2012, the reserve balance associated with these actions is $630. The Company expects to be committed to an additional $1,100 of restructuring charges in fiscal 2013 related to these actions.

A roll-forward of the non-acquisition related restructuring reserve is as follows:


	Employee Severance			Plant Closure and Other			Total

Balance at March 31, 2009	$	10,289		$	—		$	10,289
Accrued		10,107			2,263			12,370
Costs incurred		(13,276	)		(2,263	)		(15,539	)
Foreign currency impact and other		362			—			362

Balance at March 31, 2010	$	7,482		$	—		$	7,482
Accrued		4,267			—			4,267
Costs incurred		(6,945	)		—			(6,945	)
Foreign currency impact and other		116			—			116

Balance at March 31, 2011	$	4,920		$	—		$	4,920
Accrual adjustment		(681	)		—			(681	)
Accrued		4,958			—			4,958
Costs incurred		(7,966	)		—			(7,966	)
Foreign currency impact and other		(45	)		—			(45	)


Balance at March 31, 2012	$	1,186		$	—		$	1,186

The entire disclosure for restructuring and related activities. Description of restructuring activities such as exit and disposal activities, include facts and circumstances leading to the plan, the expected plan completion date, the major types of costs associated with the plan activities, total expected costs, the accrual balance at the end of the period, and the periods over which the remaining accrual will be settled.

Other (Income) Expense, Net And Charges Related To Refinancing [Abstract]

Warranty

12 Months Ended

Mar. 31, 2012

Warranty [Abstract]

Warranty

21. Warranty

The Company provides for estimated product warranty expenses when the related products are sold and are included within accrued expenses and other liabilities. Because warranty estimates are forecasts that are based on the best available information, primarily historical claims experience, claims costs may differ from amounts provided. An analysis of changes in the liability for product warranties is as follows:


Balance at March 31, 2009	$	30,914
Current year provisions		13,123
Costs incurred		(13,283	)
Foreign exchange and other		985

Balance at March 31, 2010	$	31,739
Current year provisions		20,565
Costs incurred		(17,499	)
Foreign exchange and other		1,201

Balance at March 31, 2011	$	36,006
Current year provisions		26,841
Costs incurred		(20,185	)
Foreign exchange and other		(595	)

Balance at March 31, 2012	$	42,067

Other (Income) Expense, Net And Charges Related To Refinancing

12 Months Ended

Mar. 31, 2012

Other (Income) Expense, Net And Charges Related To Refinancing

22. Other (Income) Expense, Net and Charges Related to Refinancing

Other (income) expense, net consists of the following:


	Fiscal Years Ended March 31,
	2012		2011		2010
Foreign exchange transaction losses	$	1,483	$	732	$	3,045
Secondary offering fees		—		615		150
Other		1,585		830		1,189

Total	$	3,068	$	2,177	$	4,384

Charges related to refinancing:


	Fiscal Years Ended March 31,
	2012		2011		2010
Charges related to refinancing	$	—	$	8,155	$	—

In fiscal 2011, the Company incurred charges of $8,155 in connection with the refinancing of the Company's previous credit facility. These charges included $2,308 in write offs of deferred financing fees and $5,847 of losses from discontinuing hedge accounting for the interest rate swap agreements.

Operations By Industry Segment And Geographic Area

12 Months Ended

Mar. 31, 2012

Operations By Industry Segment And Geographic Area [Abstract]

Operations By Industry Segment And Geographic Area

23. Operations by Industry Segment and Geographic Area

The Company has three reportable business segments based on geographic regions, defined as follows:

•

Americas, which includes North and South America, with segment headquarters in Reading, Pennsylvania, USA,

•

Europe, which includes Europe, the Middle East and Africa, with segment headquarters in Zurich, Switzerland, and

•

Asia, which includes Asia, Australia and Oceania, with segment headquarters in Singapore.

Summarized financial information related to the Company's business segments at March 31, 2012, 2011 and 2010 and for each of the fiscal years then ended is shown below.


	Fiscal Years Ended March 31,
	2012			2011			2010
Net sales by segment to unaffiliated customers
Europe	$	995,431		$	890,313		$	741,975
Americas		1,082,747			896,629			700,297
Asia		205,191			177,520			137,113

Total net sales	$	2,283,369		$	1,964,462		$	1,579,385

Net sales by product line
Reserve power	$	1,092,734		$	970,480		$	820,526
Motive power		1,190,635			993,982			758,859

Total net sales	$	2,283,369		$	1,964,462		$	1,579,385

Intersegment sales
Europe	$	75,652		$	55,586		$	37,449
Americas		38,115			42,141			24,848
Asia		21,182			21,349			13,237

Total intersegment sales⁽¹⁾	$	134,949		$	119,076		$	75,534

Operating earnings
Europe	$	63,872		$	55,643		$	17,649
Americas		138,894			124,515			87,156
Asia		12,133			10,469			20,502
Legal proceedings settlement income (Europe)		900			—			—
Restructuring charges (Europe)		(4,988	)		(6,813	)		(13,212	)
Restructuring charges (Americas)		—			—			(717	)
Bargain purchase gain (Europe)		—			—			2,919

Total operating earnings⁽²⁾	$	210,811		$	183,814		$	114,297

Property, plant and equipment, net
Europe	$	161,854		$	169,056		$	156,953
Americas		144,701			142,263			138,217
Asia		46,660			33,066			19,971

Total	$	353,215		$	344,385		$	315,141

Capital Expenditures
Europe	$	21,631		$	22,034		$	20,624
Americas		20,862			22,368			21,089
Asia		6,450			15,538			3,398

Total	$	48,943		$	59,940		$	45,111

Depreciation and Amortization
Europe	$	25,451		$	21,564		$	22,348
Americas		21,466			19,842			19,189
Asia		3,443			2,987			3,314

Total	$	50,360		$	44,393		$	44,851

(1)

Intersegment sales are presented on a cost plus basis which takes into consideration the effect of transfer prices between legal entities.

(2)

The Company does not allocate interest expense or other (income) expense to the reportable segments.

The Company markets its products and services in over 100 countries. Sales are attributed to countries based on the location of sale approval and acceptance. Sales to customers in the United States were 42.6%, 41.3% and 40.4% for fiscal years ended March 31, 2012, 2011 and 2010, respectively. No single country, outside the United States, exceeded 10% of consolidated net sales, and therefore deemed not material for separate disclosure.

The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 131
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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Reference 4: http://www.xbrl.org/2003/role/presentationRef
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Reference 5: http://www.xbrl.org/2003/role/presentationRef
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Reference 6: http://www.xbrl.org/2003/role/presentationRef
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Reference 7: http://www.xbrl.org/2003/role/presentationRef
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Quarterly Financial Data

12 Months Ended

Mar. 31, 2012

Quarterly Financial Data [Abstract]

Quarterly Financial Data

24. Quarterly Financial Data (Unaudited)

The Company reports interim financial information for 13-week periods, except for the first quarter, which always begins on April 1, and the fourth quarter, which always ends on March 31. The four quarters in fiscal 2012 ended on July 3, 2011, October 2, 2011, January 1, 2012, and March 31, 2012, respectively. The four quarters in fiscal 2011 ended on July 4, 2010, October 3, 2010, January 2, 2011, and March 31, 2011, respectively.


	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter		Fiscal Year
Fiscal year ended March 31, 2012
Net sales	$	569,229	$	547,140	$	574,246	$	592,754	$	2,283,369
Gross profit		121,971		114,395		130,876		145,463		512,705
Operating earnings⁽¹⁾		48,715		42,440		53,777		65,879		210,811
Net earnings		33,496		28,289		36,859		45,323		143,967
Net earnings attributable to EnerSys stockholders		33,496		28,289		36,859		45,359		144,003
Net earnings per common share attributable to EnerSys stockholders—basic	$	0.67	$	0.57	$	0.77	$	0.95	$	2.95
Net earnings per common share attributable to EnerSys stockholders—diluted	$	0.66	$	0.57	$	0.77	$	0.94	$	2.93


Fiscal year ended March 31, 2011
Net sales	$	434,969	$	472,843	$	508,596	$	548,054	$	1,964,462
Gross profit		96,614		110,721		117,900		124,609		449,844
Operating earnings⁽²⁾		37,480		44,496		48,320		53,518		183,814
Net earnings⁽³⁾		23,027		26,549		33,759		30,091		113,426
Net earnings attributable to EnerSys stockholders		23,027		26,549		33,759		30,091		113,426
Net earnings per common share attributable to EnerSys stockholders—basic	$	0.47	$	0.54	$	0.68	$	0.60	$	2.30
Net earnings per common share attributable to EnerSys stockholders—diluted	$	0.47	$	0.53	$	0.67	$	0.59	$	2.27

(1)

Included in Operating earnings were restructuring charges of $410, $902, $1,440 and $2,236 for the first, second, third and fourth quarters of fiscal 2012, respectively. Operating earnings also included a legal proceedings settlement income of $900, in the second quarter of fiscal 2012.

(2)

Included in Operating earnings were restructuring charges of $723, $2,750, $1,754 and $1,586 for the first, second, third and fourth quarters of fiscal 2011, respectively.

(3)

Included in Net earnings of fiscal 2011 were charges related to refinancing of $8,155 in the fourth quarter of fiscal 2011.

The entire disclosure for the quarterly financial data in the annual financial statements. The disclosure may include a tabular presentation of financial information for each fiscal quarter for the current and previous year, including revenues, gross profit, income or loss before extraordinary items and earnings per share data. It also includes an indication if the information in the note is unaudited, comments on the aggregate effect of year-end adjustments, and an explanation of matters or transactions that affect comparability or are pertinent to an understanding of the information furnished.

Valuation And Qualifying Accounts [Abstract]

Subsequent Events	12 Months Ended
Subsequent Events	Mar. 31, 2012
Subsequent Events [Abstract]
Subsequent Events	25. Subsequent Events On May 14, 2012, under the Company's 2010 Equity Incentive Plan, the Company granted 223,224 restricted stock units, which vest 25% each year over four-years from the date of grant, and 292,123 market share units, which vest three years from the date of grant.

Valuation And Qualifying Accounts

12 Months Ended

Mar. 31, 2012

Valuation And Qualifying Accounts

EnerSys

Valuation and Qualifying Accounts

(In Thousands)


	Balance at Beginning of Period		Additions Charged to Expense		Charge-Offs			Purchase accounting adjustments		Other(1)			Balance at End of Period
Allowance for doubtful accounts:
Fiscal year ended March 31, 2010	$	7,978	$	2,712	$	(1,257	)	$	—	$	446		$	9,879
Fiscal year ended March 31, 2011		9,879		1,513		(1,673	)		—		828			10,547
Fiscal year ended March 31, 2012		10,547		1,395		(2,012	)		—		92			10,022

Allowance for inventory valuation:
Fiscal year ended March 31, 2010	$	16,725	$	1,704	$	(7,437	)	$	—	$	686		$	11,678
Fiscal year ended March 31, 2011		11,678		8,329		(5,361	)		—		406			15,052
Fiscal year ended March 31, 2012		15,052		7,659		(7,657	)		—		(223	)		14,831

Deferred tax asset—valuation allowance:
Fiscal year ended March 31, 2010	$	57,397	$	894	$	(2,896	)	$	—	$	2,987		$	58,382
Fiscal year ended March 31, 2011		58,382		825		(2,444	)		5,340		1,514			63,617
Fiscal year ended March 31, 2012		63,617		2,457		(7,528	)		1,124		(3,311	)		56,359

(1)

Primarily the impact of currency changes.

Summary Of Significant Accounting Policies (Policy)	12 Months Ended
Summary Of Significant Accounting Policies (Policy)	Mar. 31, 2012
Summary Of Significant Accounting Policies [Abstract]
Description Of Business	*Description of Business* EnerSys and its predecessor companies have been manufacturers of industrial batteries for over 100 years. EnerSys is a global leader in stored energy solutions for industrial applications. The Company manufactures, markets and distributes industrial batteries and related products such as chargers, power equipment and battery accessories, and provides related after-market and customer-support services for industrial batteries.
Principles Of Consolidation	*Principles of Consolidation* The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries and any partially-owned subsidiaries that the Company has the ability to control. Control generally equates to ownership percentage, whereby investments that are more than 50% owned are generally consolidated, investments in affiliates of 50% or less but greater than 20% are generally accounted for using the equity method, and investments in affiliates of 20% or less are accounted for using the cost method. All intercompany transactions and balances have been eliminated in consolidation.
Foreign Currency Translation	*Foreign Currency Translation* Results of foreign operations are translated into U.S. dollars using average exchange rates during the period. The assets and liabilities are translated into U.S. dollars using exchange rates as of the balance sheet date. Gains or losses resulting from translating the foreign currency financial statements are accumulated as a separate component of accumulated other comprehensive income ("AOCI") in EnerSys' stockholders' equity and noncontrolling interests. Transaction gains and losses resulting from exchange rate changes on transactions denominated in currencies other than the functional currency of the applicable subsidiary are included in the Consolidated Statements of Income, within "Other (income) expense, net", in the year in which the change occurs.
Revenue Recognition	*Revenue Recognition* The Company recognizes revenue when the earnings process is complete. This occurs when risk and title transfers, collectibility is reasonably assured and pricing is fixed and determinable. Shipment terms are either shipping point or destination and do not differ significantly between the Company's business segments. Accordingly, revenue is recognized when risk and title are transferred to the customer. Amounts invoiced to customers for shipping and handling are classified as revenue. Taxes on revenue producing transactions are not included in net sales. The Company recognizes revenue from the service of its reserve power and motive power products when the respective services are performed. Accruals are made at the time of sale for sales returns and other allowances based on the Company's historical experience.
Freight Expense	*Freight Expense* Amounts billed to customers for outbound freight costs are classified as sales in the consolidated statements of income. Costs incurred by the Company for outbound freight costs to customers, inbound and transfer freight are classified in cost of goods sold.
Warranties	*Warranties* The Company's products are warranted for a period ranging from one to twenty years for reserve power batteries and for a period ranging from one to seven years for motive power batteries. The Company provides for estimated product warranty expenses when the related products are sold. The assessment of the adequacy of the reserve includes a review of open claims and historical experience.
Cash And Cash Equivalents	*Cash and Cash Equivalents* Cash and cash equivalents include all highly liquid investments with an original maturity of three months or less when purchased.
Concentration Of Credit Risk	*Concentration of Credit Risk* Financial instruments that subject the Company to potential concentration of credit risk consist principally of short-term cash investments and trade accounts receivable. The Company invests its cash with various financial institutions and in various investment instruments limiting the amount of credit exposure to any one financial institution or entity. The Company has bank deposits that exceed federally-insured limits. In addition, certain cash investments may be made in U.S. and foreign government bonds, or other highly rated investments guaranteed by the U.S. or foreign governments. Concentration of credit risk with respect to trade receivables is limited by a large, diversified customer base and its geographic dispersion. The Company performs ongoing credit evaluations of its customers' financial condition and requires collateral, such as letters of credit, in certain circumstances.
Accounts Receivable	*Accounts Receivable* The Company maintains allowances for doubtful accounts for estimated losses resulting from the inability of customers to make required payments. The allowance is based on management's estimate of uncollectible accounts, analysis of historical data and trends, as well as reviews of all relevant factors concerning the financial capability of its customers. Accounts receivable are considered to be past due based on how payments are received compared to the customer's credit terms. Accounts are written off when management determines the account is uncollectible.
Inventories	*Inventories* Inventories are stated at the lower of cost or market. Cost is determined using the first-in, first-out (FIFO) method. The cost of inventory consists of material, labor, and associated overhead.
Property, Plant, And Equipment	*Property, Plant, and Equipment* Property, plant, and equipment are recorded at cost and include expenditures that substantially increase the useful lives of the assets. Depreciation is provided using the straight-line method over the estimated useful lives of the assets as follows: 10 to 33 years for buildings and improvements and 3 to 15 years for machinery and equipment. Maintenance and repairs are expensed as incurred. Interest on capital projects is capitalized during the construction period.
Goodwill And Other Intangible Assets	Goodwill and Other Intangible Assets The Company records the excess of purchase price over the fair value of the tangible and identifiable intangible assets acquired as goodwill. Goodwill and indefinite-lived trade names are tested for impairment at least annually and whenever events or circumstances occur indicating that a possible impairment may have been incurred. The Company utilizes financial projections of its business segments, certain cash flow measures, as well as its market capitalization in its determination of the fair value of these assets. Finite-lived assets such as purchased and licensed technology, patents and customer lists are amortized over their estimated useful lives, generally over periods ranging from 3 to 20 years. The Company reviews the carrying values of these assets for possible impairment whenever events or changes in circumstances indicate that the carrying value of an asset may not be recoverable based on undiscounted estimated cash flows expected to result from its use and eventual disposition. The Company continually evaluates the reasonableness of the useful lives of these assets.
Impairment Of Long-Lived Assets	*Impairment of Long-Lived Assets* The Company reviews the carrying values of its property and equipment for possible impairment whenever events or changes in circumstances indicate that the carrying value of an asset may not be recoverable based on undiscounted estimated cash flows expected to result from its use and eventual disposition. The factors considered by the Company in performing this assessment include current operating results, trends and other economic factors. In assessing the recoverability of the carrying value of the property and equipment, the Company must make assumptions regarding future cash flows and other factors. If these estimates or the related assumptions change in the future, the Company may be required to record an impairment loss for these assets.
Environmental Expenditures	*Environmental Expenditures* The Company records a loss and establishes a reserve for environmental remediation liabilities when it is probable that an asset has been impaired or a liability exists and the amount of the liability can be reasonably estimated. Reasonable estimates involve judgments made by management after considering a broad range of information including: notifications, demands or settlements that have been received from a regulatory authority or private party, estimates performed by independent engineering companies and outside counsel, available facts existing and proposed technology, the identification of other potentially responsible parties, their ability to contribute and prior experience. These judgments are reviewed quarterly as more information is received and the amounts reserved are updated as necessary. However, the reserves may materially differ from ultimate actual liabilities if the loss contingency is difficult to estimate or if management's judgments turn out to be inaccurate. If management believes no best estimate exists, the minimum probable loss is accrued.
Fair Value Of Financial Instruments	*Fair Value of Financial Instruments* The fair value of the Company's cash and cash equivalents, accounts receivable and accounts payable approximate carrying value due to their short maturities. The fair value of the Company's $350,000 senior secured revolving credit facility ("2011 Credit Facility"), the 75,000 Chinese Renminbi ("RMB") credit facility ("China Term Loan"), the 273,780 Indian Rupee ("INR") term loan ("India Term Loan") and short-term debt approximate their carrying value, as they are variable rate debt and the current terms are comparable to market terms as of the balance sheet dates and are classified as Level 2. The fair value amounts of the Company's $172,500 senior unsecured 3.375% convertible notes ("Convertible Notes") represent the trading values of the Convertible Notes which is based upon quoted market prices and are classified as Level 2. Fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (an exit price). The Company and its subsidiaries use, as appropriate, a market approach (generally, data from market transactions), an income approach (generally, present value techniques and option-pricing models), and/or a cost approach (generally, replacement cost) to measure the fair value of an asset or liability. These valuation approaches incorporate inputs such as observable, independent market data and/or unobservable data that management believes are predicated on the assumptions market participants would use to price an asset or liability. These inputs may incorporate, as applicable, certain risks such as nonperformance risk, which includes credit risk. Lead contracts, foreign currency contracts and interest rate contracts generally use an income approach to measure the fair value of these contracts, utilizing readily observable inputs, such as forward interest rates (e.g., London Interbank Offered Rate—"LIBOR") and forward foreign currency exchange rates (e.g., GBP and euro) and commodity prices (e.g. London Metals Exchange), as well as inputs that may not be observable, such as credit valuation adjustments. When observable inputs are used to measure all or most of the value of a contract, the contract is classified as Level 2. Over-the-counter (OTC) contracts are valued using quotes obtained from an exchange, binding and non-binding broker quotes. Furthermore, the Company obtains independent quotes from the market to validate the forward price curves. OTC contracts include forwards, swaps and options. To the extent possible, fair value measurements utilize various inputs that include quoted prices for similar contracts or market-corroborated inputs. When unobservable inputs are significant to the fair value measurement, a contract is classified as Level 3. The Company did not have any Level 3 positions at March 31, 2012 or March 31, 2011. Additionally, Level 2 fair value measurements include adjustments for credit risk based on the Company's own creditworthiness (for net liabilities) and its counterparties' creditworthiness (for net assets). The Company assumes that observable market prices include sufficient adjustments for liquidity and modeling risks. The Company did not have any contracts that transferred between Level 2 and Level 3 as well as Level 1 and Level 2.
Derivative Financial Instruments	Derivative Financial Instruments The Company utilizes derivative instruments to mitigate volatility related to interest rates, lead prices and foreign currency exposures. The Company does not hold or issue derivative financial instruments for trading or speculative purposes. The Company recognizes derivatives as either assets or liabilities in the accompanying balance sheet and measures those instruments at fair value. Changes in the fair value of those instruments are reported in AOCI if they qualify for hedge accounting or in earnings if they do not qualify for hedge accounting. Derivatives qualify for hedge accounting if they are designated as hedge instruments and if the hedge is highly effective in achieving offsetting changes in the fair value or cash flows of the asset or liability hedged. Effectiveness is measured on a regular basis using statistical analysis and by comparing the overall changes in the expected cash flows on the lead and foreign currency forward contracts with the changes in the expected all-in cash outflow required for the lead and foreign currency purchases. This analysis is performed on the initial purchases quarterly that cover the quantities hedged. Accordingly, gains and losses from changes in derivative fair value of effective hedges are deferred and reported in AOCI until the underlying transaction affects earnings. The Company has commodity, foreign exchange and interest rate hedging authorization from the Board of Directors and has established a hedging and risk management program that includes the management of market and counterparty risk. Key risk control activities designed to ensure compliance with the risk management program include, but are not limited to, credit review and approval, validation of transactions and market prices, verification of risk and transaction limits, portfolio stress tests, sensitivity analyses and frequent portfolio reporting, including open positions, determinations of fair value and other risk management metrics. Market risk is the potential loss the Company and its subsidiaries may incur as a result of price changes associated with a particular financial or commodity instrument. The Company utilizes forward contracts, and swaps as part of its risk management strategies, to minimize unanticipated fluctuations in earnings caused by changes in commodity prices, interest rates and/or foreign currency exchange rates. All derivatives are recognized on the balance sheet at their fair value, unless they qualify for Normal Purchase Normal Sale. Credit risk is the potential loss the Company may incur due to counterparty's non-performance. The Company is exposed to credit risk from interest rate, foreign currency and commodity derivatives with financial institutions. The Company has credit policies to manage their credit risk, including the use of an established credit approval process, monitoring of counterparty positions and the use of master netting agreements. The Company has elected to offset net derivative positions under master netting arrangements. The Company does not have any positions involving cash collateral (payables or receivables) under a master netting arrangement as of March 31, 2012 and 2011. The Company does not have any credit-related contingent features associated with their derivative instruments.
Income Taxes	*Income Taxes* The Company accounts for income taxes in accordance with the Financial Accounting Standards Board ("FASB") guidance, which requires deferred tax assets and liabilities be recognized using enacted tax rates to measure the effect of temporary differences between book and tax bases on recorded assets and liabilities. FASB guidance also requires that deferred tax assets be reduced by a valuation allowance, if it is more likely than not some portion or all of the deferred tax assets will not be recognized. The Company evaluates on a quarterly basis its ability to realize deferred tax assets by assessing its valuation allowance and by adjusting the amount of such allowance, if necessary. The factors used to assess the likelihood of realization are forecasts of future taxable income and available tax planning strategies that could be implemented to realize the net deferred tax assets. In accordance with FASB guidance on accounting for uncertainty in income taxes, the Company evaluates tax positions to determine whether the benefits of tax positions are more likely than not of being sustained upon audit based on the technical merits of the tax position. For tax positions that are more likely than not of being sustained upon audit, the Company recognizes the largest amount of the benefit that is greater than 50% likely of being realized upon ultimate settlement. For tax positions that are not more likely than not of being sustained upon audit, the Company does not recognize any portion of the benefit. If the more likely than not threshold is not met in the period for which a tax position is taken, the Company may subsequently recognize the benefit of that tax position if the tax matter is effectively settled, the statute of limitations expires, or if the more likely than not threshold is met in a subsequent period.
Deferred Financing Fees	*Deferred Financing Fees* Debt issuance costs that are incurred by the Company in connection with the issuance of debt are deferred and amortized to interest expense over the life of the underlying indebtedness, adjusted to reflect any early repayments.
Retirement Plans	Retirement Plans The Company accounts for retirement plans in accordance with FASB guidance on employers' accounting for defined benefit pension benefit plans, which requires an entity to recognize in its statement of financial position an asset for a defined benefit postretirement plan's overfunded status or a liability for a plan's underfunded status, and to measure a defined benefit postretirement plan's assets and obligation that determine its funded status as of the end of the balance sheet date. The Company uses certain assumptions in the calculation of the actuarial valuations of its defined benefit plans. These assumptions include discount rate, rates of increase in compensation levels and expected long-term rates of return of plan assets. If actual results are less favorable than those projected by the Company, additional expense may be required.
Stock-Based Compensation Plans	Stock-Based Compensation Plans The Company accounts for stock compensation in accordance with FASB guidance, which requires the Company to measure the cost of employee services received in exchange for the award of an equity instrument based on the grant-date fair value of the award, with such cost recognized over the applicable vesting period. In addition, the guidance requires an entity to provide certain disclosures in order to assist in understanding the nature of share-based payment transactions and the effects of those transactions on the financial statements. Market Share Units The fair value of the market share units is estimated at the date of grant using a binomial lattice model with the following assumptions: a risk-free interest rate, dividend yield, time to maturity and expected volatility. These units vest and are settled in common stock on the third anniversary of the date of grant. Market share units are converted into between zero and two shares of common stock for each unit granted at the end of a three-year performance cycle. The conversion ratio is calculated by dividing the average closing share price of the Company's common stock during the ninety calendar days immediately preceding the vesting date by the average closing share price of the Company's common stock during the ninety calendar days immediately preceding the grant date, with the resulting quotient capped at two. This quotient is then multiplied by the number of market share units granted to yield the number of shares of common stock to be delivered on the vesting date. The Company recognizes compensation expense using the straight-line method over the life of the market share units. Restricted Stock Units The fair value of restricted stock units is based on the closing market price of the Company's common stock on the date of grant. These awards generally vest, and are settled in common stock, at 25% per year, over a four-year period from the date of grant. The Company recognizes compensation expense using the straight-line method over the life of the restricted stock units. Stock Options The fair value of the options granted is estimated at the date of grant using the Black-Scholes option-pricing model utilizing assumptions based on historical data and current market data. The assumptions include expected term of the options, risk-free interest rate, expected volatility, and dividend yield. The expected term represents the expected amount of time that options granted are expected to be outstanding, based on historical and forecasted exercise behavior. The risk-free rate is based on the rate at grant date of zero-coupon U.S. Treasury Notes with a term equal to the expected term of the option. Expected volatility is estimated using historical volatility rates based on historical weekly price changes. The Company's dividend yield is based on historical data. The Company recognizes compensation expense using the straight-line method over the vesting period of the options.
Earnings Per Share	*Earnings Per Share* Basic earnings per common share ("EPS") are computed by dividing net earnings available to common stockholders by the weighted average number of common shares outstanding for the period. Diluted EPS reflects the potential dilution that would occur if securities or other contracts to issue common stock were exercised or converted into common stock. At March 31, 2012, 2011 and 2010, the Company had outstanding stock options, restricted stock units, market share units and Convertible Notes, which could potentially dilute basic earnings per share in the future.
Segment Reporting	*Segment Reporting* FASB guidance defines that a segment for reporting purposes is based on the financial performance measures that are regularly reviewed by the chief operating decision maker to assess segment performance and to make decisions about a public entity's allocation of resources. Based on this guidance, the Company reports its segment results based upon the three geographical regions of operations—Americas, Europe and Asia.
Use Of Estimates	*Use of Estimates* The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates.
Reclassifications	*Reclassifications* Certain amounts in the prior years' financial statements have been reclassified to conform to the current-year presentation.

Inventories (Tables)

12 Months Ended

Mar. 31, 2012

Inventories [Abstract]

Summary Of Net Inventories


	March 31,
	2012		2011
Raw materials	$	100,538	$	92,928
Work-in-process		111,629		100,261
Finished goods		149,607		141,814


Total	$	361,774	$	335,003

Property, Plant, And Equipment (Tables)

12 Months Ended

Mar. 31, 2012

Property, Plant, And Equipment [Abstract]

Summary Of Property, Plant, And Equipment


	March 31,
	2012			2011
Land, buildings, and improvements	$	201,038		$	174,887
Machinery and equipment		511,599			475,818
Construction in progress		29,779			51,662

		742,416			702,367
Less accumulated depreciation		(389,201	)		(357,982	)


Total	$	353,215		$	344,385

Goodwill And Other Intangible Assets (Tables)

12 Months Ended

Mar. 31, 2012

Goodwill And Other Intangible Assets [Abstract]

Schedule Of Company's Other Intangible Assets


	March 31,
	2012							2011
	Gross Amount		Accumulated Amortization			Net Amount		Gross Amount		Accumulated Amortization			Net Amount
Indefinite-lived intangible assets:
Trademarks	$	86,745	$	(953	)	$	85,792	$	83,021	$	(953	)	$	82,068
Finite-lived intangible assets:
Customer relationships		14,330		(2,839	)		11,491		11,064		(1,880	)		9,184
Non-compete		2,602		(1,224	)		1,378		2,117		(954	)		1,163
Patents		5,230		(615	)		4,615		3,402		(210	)		3,192
Trademarks		2,003		(643	)		1,360		3,771		(559	)		3,212
Licenses		2,640		(194	)		2,446		82		(82	)		-


Total	$	113,550	$	(6,468	)	$	107,082	$	103,457	$	(4,638	)	$	98,819

Schedule Of Changes In The Carrying Amount Of Goodwill By Business Segment


	Fiscal year ended March 31, 2012
	Europe			Americas			Asia		Total
Balance at beginning of year	$	177,881		$	143,225		$	22,560	$	343,666
Goodwill acquired during the year		1,250			7,973			1,500		10,723
Adjustments related to the finalization of purchase accounting for prior year acquisitions		374			5			-		379
Foreign currency translation		(7,977	)		(449	)		719		(7,707	)


Balance at end of year	$	171,528		$	150,754		$	24,779	$	347,061


	Fiscal year ended March 31, 2011
	Europe		Americas		Asia		Total
Balance at beginning of year	$	162,641	$	132,915	$	21,709	$	317,265
Goodwill acquired during the year		7,710		7,591		-		15,301
Adjustments related to the finalization of purchase accounting for prior year acquisitions		24		2,250		-		2,274
Foreign currency translation		7,506		469		851		8,826


Balance at end of year	$	177,881	$	143,225	$	22,560	$	343,666

Tabular disclosure of goodwill by reportable segment and in total. Disclosure details may include, but are not limited to, the carrying amount of goodwill, goodwill acquired during the year, goodwill impairment losses recognized, goodwill written-off due to the sale of a business unit, goodwill not yet allocated, and any other changes to goodwill.

Prepaid And Other Current Assets [Abstract]

Prepaid And Other Current Assets (Tables)

12 Months Ended

Mar. 31, 2012

Schedule Of Prepaid And Other Current Assets


	March 31,
	2012		2011
Prepaid non income taxes	$	23,737	$	22,753
Non-trade receivables		8,247		8,214
Prepaid income taxes		7,716		15,986
Lead hedges		—		9,575
Other		12,693		13,675

Total	$	52,393	$	70,203

Accrued Expenses (Tables)

12 Months Ended

Mar. 31, 2012

Accrued Expenses [Abstract]

Summary Of Accrued Expenses


	March 31,
	2012		2011
Payroll and benefits	$	55,595	$	58,794
Accrued selling expenses		26,269		24,257
Warranty		19,274		16,218
Income taxes payable		16,979		15,591
VAT and other non-income taxes		10,966		11,937
Freight		12,314		10,208
Deferred income		12,057		7,107
Interest rate swaps		3,628		—
Interest		2,040		2,471
Pension and social security		1,696		1,854
Restructuring		1,186		5,323
Other		26,399		30,940

Total	$	188,403	$	184,700

Debt (Tables)

12 Months Ended

Mar. 31, 2012

Debt [Abstract]

Schedule Of Long-Term Debt


	March 31,
	2012		2011
3.375% Convertible Notes, net of discount, due 2038	$	148,272	$	141,837
2011 Credit Facility due 2016		79,400		100,000
China Term Loan due 2017		6,034		6,112
India Term Loan due 2017		5,383		-
Other		40		43


		239,129		247,992
Less current portion		2,540		43


Total long-term debt	$	236,589	$	247,949

Components Of Net Carrying Amount Of Convertible Notes


	March 31,			March 31,
	2012			2011
Principal	$	172,500		$	172,500
Unamortized discount		(24,228	)		(30,663	)

Net carrying amount	$	148,272		$	141,837

Carrying amount of equity component	$	29,850		$	29,850

Summary Of Aggregate Maturities Of Long-Term Debt


2013	$	2,540
2014		2,450
2015		2,450
2016		254,350
2017		1,567
Thereafter


	$	263,357

Tabular disclosure of long-debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the entity, if longer.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 22
-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28541-108399

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21506-112644

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21538-112644

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21521-112644

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=6584090&loc=d3e28878-108400

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6479336&loc=d3e64711-112823

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(e),(f))
-URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e23780-122690

Schedule Of Capital And Operating Leases

Leases (Tables)

12 Months Ended

Mar. 31, 2012

Leases [Abstract]


	Capital Leases		Operating Leases
2013	$	451	$	18,268
2014		475		13,478
2015		84		10,108
2016		14		6,981
2017		7		5,008
Thereafter		—		3,588


Total minimum lease payments		1,031	$	57,431


Amounts representing interest		101


Net minimum lease payments, including current portion of $409	$	930

Other Liabilities (Tables)

12 Months Ended

Mar. 31, 2012

Other Liabilities [Abstract]

Schedule Of Other Long-Term Liabilities


	March 31,
	2012		2011
Pension and profit sharing obligation	$	35,804	$	29,297
Warranty		22,793		19,788
Long-term income taxes liabilities		13,520		11,320
Deferred income		6,094		3,839
Interest rate swap liabilities		244		5,847
Other		14,013		6,552


Total	$	92,468	$	76,643

Fair Value Of Financial Instruments (Tables)

12 Months Ended

Mar. 31, 2012

Fair Value Of Financial Instruments [Abstract]

Financial Assets And (Liabilities), Measured At Fair Value On A Recurring Basis


	Total Fair Value Measurement March 31, 2012			Quoted Price in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)			Significant Unobservable Inputs (Level 3)
Interest rate swap agreements	$	(3,872	)	$	—	$	(3,872	)	$	—
Lead forward contracts		(851	)		—		(851	)		—
Foreign currency forward contracts		782			—		782			—

Total derivatives	$	(3,941	)	$	—	$	(3,941	)	$	—


	Total Fair Value Measurement March 31, 2011			Quoted Price in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)			Significant Unobservable Inputs (Level 3)
Interest rate swap agreements	$	(5,847	)	$	—	$	(5,847	)	$	—
Lead forward contracts		9,575			—		9,575			—
Foreign currency forward contracts		(2,591	)		—		(2,591	)		—

Total derivatives	$	1,137		$	—	$	1,137		$	—

Carrying Amounts And Estimated Fair Values Of Company's Financial Instruments


	March 31, 2012						March 31, 2011
	Carrying Amount			Fair Value			Carrying Amount			Fair Value
Financial assets:
Derivatives ⁽¹⁾	$	782		$	782		$	9,575		$	9,575

Financial liabilities:
Convertible Notes	$	148,272	⁽²⁾	$	200,100	⁽³⁾	$	141,837	⁽²⁾	$	215,625	⁽³⁾
Derivatives ⁽¹⁾		4,723			4,723			8,438			8,438

⁽¹⁾	Represents interest rate swap agreements, lead and foreign currency hedges (see Note 12 for asset and liability positions of the interest rate swap agreements, lead and foreign currency hedges at March 31, 2012 and March 31, 2011).

⁽²⁾	The carrying amounts of the Convertible Notes at March 31, 2012 and March 31, 2011 represent the $172,500 principal value, less the unamortized debt discount (see Note 8).

⁽³⁾	The fair value amounts of the Convertible Notes represent the trading values of the Convertible Notes with a principal value of $172,500 at March 31, 2012 and March 31, 2011.

Tabular disclosure of the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments, assets, and liabilities. Such certain disclosures about the financial instruments, assets, and liabilities include: (1) the fair value of the required items together with their carrying amounts (as appropriate) and (2) the methodology and assumptions used in developing such estimates of fair value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 107
-Paragraph 10
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 107
-Paragraph 14
-Subparagraph a
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 107
-Paragraph 15
-Subparagraph b-d
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 157
-Paragraph 32
-Subparagraph a, c(1), c(2), c(3), d
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 159
-Paragraph 18
-Subparagraph c(2), d, e, f
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 159
-Paragraph 19
-Subparagraph a, b, c(1), d(1)
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6947722&loc=d3e13433-108611

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=6947722&loc=d3e13467-108611

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=6947722&loc=d3e13476-108611

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 30
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6957238&loc=d3e14172-108612

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19207-110258

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6447952&loc=d3e13220-108610

Tabular disclosure of the fair value measurement of assets and liabilities which includes [financial] instruments measured at fair value that are classified in stockholders' equity. Such assets and liabilities may be measured on a recurring or nonrecurring basis. The disclosures which may be required or desired include: (1) for assets and liabilities measured on a recurring basis, disclosure may include: (a) the fair value measurements at the reporting date; (b) the level within the fair value hierarchy in which the fair value measurements in their entirety fall, segregating fair value measurements using quoted prices in active markets for identical assets or liabilities (Level 1), significant other observable inputs (Level 2), and significant unobservable inputs (Level 3); (c) for fair value measurements using significant unobservable inputs (Level 3), a reconciliation of the beginning and ending balances, separately presenting changes during the period attributable to the following: (i) total gains or losses for the period (realized and unrealized), segregating those gains or losses included in earnings (or changes in net assets), and a description of where those gains or losses included in earnings (or changes in net assets) are reported in the statement of income (or activities); (ii) purchases, sales, issuances, and settlements (net); (iii) transfers in and transfers out of Level 3 (for example, transfers due to changes in the observability of significant inputs); (d) the amount of the total gains or losses for the period in subparagraph (c) (i) above included in earnings (or changes in net assets) that are attributable to the change in unrealized gains or losses relating to those assets and liabilities still held at the reporting date and a description of where those unrealized gains or losses are reported in the statement of income (or activities); (e) the valuation technique(s) used to measure fair value and a discussion of changes in valuation techniques, if any, during the period and (2) for assets and liabilities that are measured at fair value on a nonrecurring basis (for example, impaired assets) disclosure may include, in addition to (a) above: (a) the reasons for the fair value measurements recorded; (b) the same as (b) above; (c) for fair value measurements using significant unobservable inputs (Level 3), a description of the inputs and the information used to develop the inputs; and (d) the valuation technique(s) used to measure fair value and a discussion of changes, if any, in the valuation technique(s) used to measure similar assets and/or liabilities in prior periods. Where the quoted price in an active market for the identical liability is not available, the Level 1 input is the quoted price of an identical liability when traded as an asset.

Derivative Financial Instruments [Abstract]

Derivative Financial Instruments (Tables)

12 Months Ended

Mar. 31, 2012

Mar. 31, 2011

Mar. 31, 2010

Fair Value Of Derivative Instruments In The Consolidated Balance Sheets


	Derivatives and Hedging Activities Designated as Cash Flow Hedges				Derivatives and Hedging Activities Not Designated as Hedging Instruments
	March 31, 2012		March 31, 2011		March 31, 2012		March 31, 2011
Prepaid and other current assets
Lead hedge forward contracts	$	—	$	9,575	$	—	$	—
Foreign currency forward contracts		670		—		112		—
Other assets		30		—		—		—

Total assets	$	700	$	9,575	$	112	$	—

Accrued expenses
Interest rate swap agreements	$	—	$	—	$	3,628	$	—
Lead hedge forward contracts		881		—		—		—
Foreign currency forward contracts		—		2,591		—		—
Other liabilities
Interest rate swap agreements		—		—		244		5,847

Total liabilities	$	881	$	2,591	$	3,872	$	5,847

The Effect Of Derivative Instruments On The Consolidated Statements Of Income


Derivatives Designated as Cash Flow Hedges	Gain (Loss) Recognized in AOCI on Derivative (Effective Portion)			Location of Gain (Loss) Reclassified from AOCI into Income (Effective Portion)	Gain (Loss) Reclassified from AOCI into Income (Effective Portion)

Lead hedge forward contracts	$	(9,731	)	Cost of goods sold	$	(831	)
Foreign currency forward contracts		(152	)	Cost of goods sold		(3,882	)

Total	$	(9,883	)		$	(4,713	)


Derivatives in a Cash Flow Hedging Relationship	Gain (Loss) Recognized in AOCI on Derivative (Effective Portion)			Location of Gain (Loss) Reclassified from AOCI into Income (Effective Portion)	Gain (Loss) Reclassified from AOCI into Income (Effective Portion)

Interest rate swap contracts	$	(2,835	)	Interest expense	$	(6,698	)
Lead hedge forward contracts		15,930		Cost of goods sold		6,417
Foreign currency forward contracts		(4,031	)	Cost of goods sold		471

Total	$	9,064			$	190


Derivatives in a Cash Flow Hedging Relationship	Gain (Loss) Recognized in AOCI on Derivative (Effective Portion)			Location of Gain (Loss) Reclassified from AOCI into Income (Effective Portion)	Gain (Loss) Reclassified from AOCI into Income (Effective Portion)
Interest rate swap contracts	$	(3,141	)	Interest expense	$	(7,059	)
Lead hedge forward contracts		9,844		Cost of goods sold		11,973
Foreign currency forward contracts		2,679		Cost of goods sold		428

Total	$	9,382				$5,342

Effect Of Derivative Instruments



Derivatives Not Designated as Hedging Instruments	Location of Gain (Loss) Recognized in Income on Derivative	Gain (Loss)
Interest rate swap contracts	Other (income) expense, net	$	(977	)
Foreign currency forward contracts	Other (income) expense, net		(106	)

Total		$	(1,083	)



Derivatives Not Designated as Hedging Instruments	Location of Gain (Loss) Recognized in Income on Derivative	Gain (Loss)
Interest rate swap contracts	Charges related to refinancing	$	(5,847	)

Total		$	(5,847	)

Income Taxes (Tables)

12 Months Ended

Mar. 31, 2012

Income Taxes [Abstract]

Income Tax Expense


	Fiscal year ended March 31,
	2012			2011			2010
Current:
Federal	$	30,459		$	24,232		$	9,000
State		3,778			2,736			(981	)
Foreign		16,282			14,114			9,957

Total current		50,519			41,082			17,976
Deferred:
Federal		(1,609	)		(1,358	)		4,678
State		(962	)		2,010			852
Foreign		(656	)		(3,716	)		1,445

Total deferred		(3,227	)		(3,064	)		6,975

Income tax expense	$	47,292		$	38,018		$	24,951

Earnings Before Income Taxes


	Fiscal year ended March 31,
	2012		2011		2010
United States	$	87,597	$	57,710	$	37,418
Foreign		103,662		93,734		49,837

Earnings before income taxes	$	191,259	$	151,444	$	87,255

Deferred Tax Assets And Liabilities


	March 31,
	2012			2011
Deferred tax assets:
Accounts receivable	$	1,111		$	1,304
Inventories		6,707			6,669
Net operating loss carryforwards		71,773			78,236
Accrued liabilities		26,997			22,061
Other assets		10,228			9,200

Gross deferred tax assets		116,816			117,470
Less valuation allowance		(56,359	)		(63,617	)

Total deferred tax assets		60,457			53,853
Deferred tax liabilities:
Property, plant and equipment		30,957			31,945
Other intangible assets		46,628			43,440
Convertible Notes		21,616			20,727
Other liabilities		2,400			4,992

Total deferred tax liabilities		101,601			101,104

Net deferred tax liabilities	$	(41,144	)	$	(47,251	)

Reconciliation Of Income Taxes At The Statutory Rate


	Fiscal year ended March 31,
	2012			2011			2010
United States statutory income tax expense (at 35%)	$	66,962		$	53,005		$	30,539
Increase (decrease) resulting from:
State income taxes, net of federal effect		1,592			3,035			(116	)
Nondeductible expenses, domestic manufacturing deduction and other		1,587			(1,848	)		3,799
Effect of foreign operations		(20,028	)		(14,841	)		(9,253	)
Valuation allowance		(2,821	)		(1,333	)		(18	)

Income tax expense	$	47,292		$	38,018		$	24,951

Reconciliation Of Unrecognized Tax Benefits


March 31, 2009	$	13,305
Increases related to current year tax positions		919
Increases related to prior year tax positions due to foreign currency translation		5
Decreases related to prior year tax position settled		(2,940	)
Lapse of statute of limitations		(539	)

March 31, 2010		10,750
Increases related to current year tax positions		2,896
Increases related to prior year tax positions		324
Increases related to prior year tax positions due to foreign currency translation		122
Decreases related to prior year tax position settled		(3,145	)
Lapse of statute of limitations		(302	)

March 31, 2011		10,645
Increases related to current year tax positions		5,032
Increases related to prior year tax positions		182
Increases related to prior year tax positions due to foreign currency translation		(28	)
Decreases related to prior year tax position settled		—
Lapse of statute of limitations		(2,886	)

March 31, 2012	$	12,945

Retirement Plans (Tables)

12 Months Ended

Mar. 31, 2012

Retirement Plans [Abstract]

Components Of Net Periodic Pension Cost


	United States Plans									International Plans
	Fiscal Year Ended March 31,									Fiscal Year Ended March 31,
	2012			2011			2010			2012			2011			2010
Service cost	$	285		$	250		$	224		$	645		$	603		$	621
Interest cost		668			646			635			2,504			2,503			2,520
Expected return on plan assets		(706	)		(624	)		(491	)		(1,787	)		(1,615	)		(1,256	)
Amortization and deferral		238			248			458			32			53			(43	)

Net periodic benefit cost	$	485		$	520		$	826		$	1,394		$	1,544		$	1,842

Summary Of Change In Projected Benefit Obligation


	United States Plans						International Plans
	March 31,						March 31,
	2012			2011			2012			2011
Change in projected benefit obligation
Benefit obligation at the beginning of the period	$	11,903		$	10,992		$	48,881		$	46,851
Service cost		285			250			645			603
Interest cost		668			646			2,504			2,503
Benefits paid, inclusive of plan expenses		(615	)		(581	)		(1,709	)		(1,481	)
Plan settlements		—			—			(40	)		—
Plan amendments		—			108			—			817
Plan combinations (including newly material plans)		—			—			—			337
Experience (gain) loss		1,799			488			5,442			(3,366	)
Foreign currency translation adjustment		—			—			(1,828	)		2,617

Benefit obligation at the end of the period	$	14,040		$	11,903		$	53,895		$	48,881

Summary Of Change In Plan Assets


	United States Plans						International Plans
	March 31,						March 31,
	2012			2011			2012			2011
Change in plan assets
Fair value of plan assets at the beginning of the period	$	8,746		$	7,859		$	25,779		$	22,712
Actual return on plan assets		420			1,102			1,555			1,751
Employer contributions		641			366			1,505			1,424
Benefits paid, inclusive of plan expenses		(615	)		(581	)		(1,709	)		(1,481	)
Plan settlements		—			—			(40	)		—
Foreign currency translation adjustments		—			—			(148	)		1,373

Fair value of plan assets at the end of the period	$	9,192		$	8,746		$	26,942		$	25,779

Funded status deficit	$	(4,848	)	$	(3,157	)	$	(26,953	)	$	(23,102	)

Summary Of Amounts Recognized In The Balance Sheet


	March 31,
	2012			2011
Amounts recognized in the consolidated balance sheets consist of:
Other assets	$	260		$	2,513
Accrued expenses		(1,309	)		(1,369	)
Other liabilities		(30,752	)		(27,403	)

	$	(31,801	)	$	(26,259	)

Summary Of Amounts Recorded In AOCI Before Taxes


	March 31,
	2012			2011			2010
Amounts recorded in AOCI before taxes:
Prior service credit (cost)	$	(922	)	$	(1,054	)	$	(132	)
Net gain (loss)		(11,176	)		(3,712	)		(7,344	)

Net amount recognized	$	(12,098	)	$	(4,766	)	$	(7,476	)

Summary Of Changes In AOCI


	March 31,
	2012			2011			2010
Changes in plan assets and benefit obligations:
New prior service cost	$	—		$	905		$	—
Net loss /(gain) arising during the year		7,757			(3,505	)		753
Effect of exchange rates on amounts included in AOCI		(176	)		151			40
Amounts recognized as a component of net periodic benefit costs:
Amortization or curtailment recognition of prior service credit /(cost)		(83	)		(62	)		(142	)
Amortization or settlement recognition of net gain/(loss)		(187	)		(250	)		(333	)

Total recognized in other comprehensive income	$	7,311		$	(2,761	)	$	318

Summary Of Recognized Components Of Net Periodic Pension Cost Included In Accumulated Other Comprehensive Income


Net loss	$	(81	)
Net prior service cost		(534	)

Net amount expected to be recognized	$	(615	)

Summary Of Accumulated Benefit Obligation Related To All Defined Pension Plans


	United States Plans				International Plans
	March 31,				March 31,
	2012		2011		2012		2011
All defined benefit plans:
Accumulated benefit obligation	$	14,040	$	11,903	$	50,416	$	46,225
Unfunded defined benefit plans:
Projected benefit obligation		—		—		26,892		25,533
Accumulated benefit obligation		—		—		25,508		24,413
Defined benefit plans with an accumulated benefit obligation in excess of the fair value of plan assets:
Projected benefit obligation		14,040		11,903		28,003		25,560
Accumulated benefit obligation		14,040		11,903		26,445		24,440
Fair value of plan assets		9,192		8,746		789		—

Significant Assumptions Used To Determine The Net Periodic Benefit Cost


	United States Plans									International Plans
	March 31,									March 31,
	2012			2011			2010			2012			2011			2010
Discount rate		5.7	%		6.0	%		6.5	%		4.0-5.5	%		4.3-6.0	%		3.8-6.0	%
Expected return on plan assets		8.0			8.0			8.0			5.5-7.0			5.5-7.0			5.5-7.0
Rate of compensation increase		N/A			N/A			N/A			2.0-4.0			2.0-3.5			2.0-3.5

Significant Assumptions Used To Determine The Projected Benefit Obligations


	United States Plans						International Plans
	March 31,						March 31,
	2012			2011			2012			2011
Discount rate		4.8	%		5.7	%		2.5-5.5	%		4.0-5.5	%
Expected return on plan assets		8.0			8.0			5.5-7.0			5.5-7.0
Rate of compensation increase		N/A			N/A			2.0-4.0			2.0-4.0

Summary Of Pension Plan Investments Measured At Fair Value


	March 31, 2012
	United States Plans								International Plans
	Total Fair Value Measurement		Quoted Price In Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total Fair Value Measurement		Quoted Price In Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Asset Category:
Cash and Cash Equivalents	$	868	$	868	$	—	$	—	$	—	$	—	$	—	$	—
Equity Securities
US^(a)		5,067		5,067		—		—		2,742		2,742		—		—
International^(b)		837		837		—		—		14,728		14,728		—		—
Fixed Income^(c)		2,420		2,420		—		—		9,472		9,472		—		—

Total	$	9,192	$	9,192	$	—	$	—	$	26,942	$	26,942	$	—	$	—


	March 31, 2011
	United States Plans								International Plans
	Total Fair Value Measurement		Quoted Price In Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total Fair Value Measurement		Quoted Price In Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Asset Category:
Cash and Cash Equivalents	$	528	$	528	$	—	$	—	$	—	$	—	$	—	$	—
Equity Securities
US^(a)		4,839		4,839		—		—		2,521		2,521		—		—
International^(b)		840		840		—		—		13,600		13,600		—		—
Fixed Income^(c)		2,539		2,539		—		—		9,658		9,658		—		—

Total	$	8,746	$	8,746	$	—	$	—	$	25,779	$	25,779	$	—	$	—

(a)	US equities include companies that are well diversified by industry sector and equity style (i.e., growth and value strategies). Active and passive management strategies are employed. Investments are primarily in large capitalization stocks and, to a lesser extent, mid- and small-cap stocks.

(b)

(c)	Fixed income consists primarily of investment grade bonds from diversified industries.

Summary Of Estimated Future Benefit Payments


	Pension Benefits
2013	$	2,173
2014		2,319
2015		2,445
2016		2,674
2017		2,993
Years 2018-2022		17,281

Stockholders' Equity (Tables)

12 Months Ended

Mar. 31, 2012

Stockholders' Equity [Abstract]

Change In Number Of Shares Of Common Stock Outstanding


Shares outstanding as of March 31, 2011	50,034,353
Repurchase of common shares	(2,646,885	)
Shares issued as part of equity-based compensation plans, net of equity awards surrendered for option price and taxes	412,661

Shares outstanding as of March 31, 2012	47,800,129

Components Of Accumulated Other Comprehensive Income


	Beginning Balance			Before-Tax Amount			Tax Benefit (Expense)			Net-of-Tax Amount			Ending Balance
March 31, 2012
Pension funded status adjustment	$	(3,512	)	$	(7,311	)	$	1,841		$	(5,470	)	$	(8,982	)
Unrealized gain (loss) on derivative instruments		4,436			(5,170	)		1,909			(3,261	)		1,175
Foreign currency translation adjustment		114,256			(32,356	)		—			(32,356	)		81,900

Accumulated other comprehensive income	$	115,180		$	(44,837	)	$	3,750		$	(41,087	)	$	74,093

March 31, 2011
Pension funded status adjustment	$	(5,479	)	$	2,761		$	(794	)	$	1,967		$	(3,512	)
Unrealized gain (loss) on derivative instruments		(5,034	)		14,721			(5,251	)		9,470			4,436
Foreign currency translation adjustment		77,717			36,539			—			36,539			114,256

Accumulated other comprehensive income	$	67,204		$	54,021		$	(6,045	)	$	47,976		$	115,180

March 31, 2010
Pension funded status adjustment	$	(4,794	)	$	(318	)	$	(367	)	$	(685	)	$	(5,479	)
Unrealized gain (loss) on derivative instruments		(7,660	)		4,047			(1,421	)		2,626			(5,034	)
Foreign currency translation adjustment		46,509			31,208			—			31,208			77,717

Accumulated other comprehensive income	$	34,055		$	34,937		$	(1,788	)	$	33,149		$	67,204

Stock-Based Compensation (Tables)

12 Months Ended

Mar. 31, 2012

Stock-Based Compensation [Abstract]

Summary Of Weighted Average Fair Value Of Options Granted


	2010			2010
	10 Year Options			3.5 Year Options
Exercise price	$	16.20		$	16.24
Risk-free interest rate		2.01	%		0.93	%
Dividend yield		0	%		0	%
Expected life		5years			2years
Expected volatility		56.6	%		56.6	%
Weighted average fair value	$	8.35		$	5.15

Summary Of Stock Option Activity


	Number of Options			Weighted Average Remaining Contract Term (Years)		Weighted Average Exercise Price		Aggregate Intrinsic Value
Options outstanding as of March 31, 2009		2,643,175			4.2	$	16.70	$	1,752
Granted		539,506					16.21		—
Exercised		(667,862	)				12.22		7,125
Canceled		(83,586	)				21.43		522

Options outstanding as of March 31, 2010		2,431,233			4.0	$	17.69	$	19,191
Exercised		(1,415,391	)				15.34		18,482
Canceled		(155,063	)				29.32		9

Options outstanding as of March 31, 2011		860,779			6.2	$	19.52	$	17,129
Exercised		(227,116	)				15.82		3,691

Options outstanding as of March 31, 2012		633,663			6.1	$	20.85	$	8,879

Options exercisable as of March 31, 2012		523,626			5.9	$	21.82	$	6,826

Options expected to vest after March 31, 2012		110,037			7.1	$	16.20	$	2,053

Summary Of Information Regarding Stock Options Outstanding And Exercisable


	Options Outstanding						Options Exercisable
Range of Exercise Prices	Number of Options		Weighted Average Remaining Contractual Life		Weighted Average Exercise Price		Number of Options		Weighted Average Exercise Price
$10.01-15.00		65,954		3.1	$	14.12		65,954	$	14.12
$15.01-20.00		361,661		6.6		16.75		251,624		16.99
Over $20.00		206,048		6.1		30.19		206,048		30.19


		633,663		6.1	$	20.85		523,626	$	21.82

Summary Of Changes Of Non-Vested Options


	Number of Options			Weighted Average Grant-Date Fair Value
Nonvested at March 31, 2011		357,903		$	8.70
Vested		(247,866	)		9.06


Nonvested at March 31, 2012		110,037		$	7.87

Summary Of The Changes In Restricted Stock Units And Market Share Units


	Restricted Stock Units (RSU) / Market Share Units (MSU)
	Number of RSU and MSU			Weighted Average Grant Date Fair Value

Non-vested awards as of March 31, 2011		865,392		$	23.97
Granted		364,395			40.76
Vested		(259,151	)		22.28
Canceled		(6,833	)		11.49

Non-vested awards as of March 31, 2012		963,803		$	30.84

Tabular disclosure of components of a stock option or other award plan under which equity-based compensation is awarded to employees, typically comprised of the amount of unearned compensation (deferred compensation cost), compensation expense, and changes in the quantity and fair value of the shares (or other type of equity) granted, exercised, forfeited, and issued and outstanding pertaining to that plan. Disclosure may also include nature and general terms of such arrangements that existed during the period and potential effects of those arrangements on shareholders, effect of compensation cost arising from equity-based payment arrangements on the income statement, method of estimating the fair value of the goods or services received, or the fair value of the equity instruments granted, during the period, cash flow effects resulting from equity-based payment arrangements and, for registrants that accelerate vesting of out of the money share options, reasons for the decision to accelerate.

Reconciliation From Basic To Diluted Average Common Shares And Net Earnings Per Common Share

Earnings Per Share (Tables)

12 Months Ended

Mar. 31, 2012

Earnings Per Share [Abstract]


	March 31,
	2012		2011		2010

Net earnings attributable to EnerSys stockholders	$	144,003	$	113,426	$	62,304


Average common shares:
Basic (weighted-average outstanding shares)		48,748,205		49,376,132		48,122,207
Dilutive potential common shares from exercise and lapse of equity awards, net of shares assumed reacquired		467,830		668,114		711,888


Diluted (weighted-average outstanding shares)		49,216,035		50,044,246		48,834,095


Basic earnings per common share attributable to EnerSys stockholders	$	2.95	$	2.30	$	1.29


Diluted earnings per common share attributable to EnerSys stockholders	$	2.93	$	2.27	$	1.28


Anti-dilutive equity awards not included in weighted average common shares — diluted		221,097		—		383,696

Restructuring Plans (Tables)

12 Months Ended

Mar. 31, 2012

Restructuring Cost and Reserve [Line Items]

Acquisition And Non-Acquisition Related Restructuring Reserve


	Employee Severance			Plant Closure and Other			Total

Balance at March 31, 2009	$	—		$	—		$	—
Accrued		1,269			—			1,269
Costs incurred		—			—			—
Foreign currency impact and other		23			—			23

Balance at March 31, 2010	$	1,292		$	—		$	1,292
Accrued		108			2,438			2,546
Costs incurred		(1,107	)		(2,313	)		(3,420	)
Foreign currency impact and other		(36	)		21			(15	)

Balance at March 31, 2011	$	257		$	146		$	403
Accrued		81			630			711
Costs incurred		(338	)		(776	)		(1,114	)


Balance at March 31, 2012	$	—		$	—		$	—

Non-Acquisition Related Restructuring Reserve [Member]

Restructuring Cost and Reserve [Line Items]

Acquisition And Non-Acquisition Related Restructuring Reserve


	Employee Severance			Plant Closure and Other			Total

Balance at March 31, 2009	$	10,289		$	—		$	10,289
Accrued		10,107			2,263			12,370
Costs incurred		(13,276	)		(2,263	)		(15,539	)
Foreign currency impact and other		362			—			362

Balance at March 31, 2010	$	7,482		$	—		$	7,482
Accrued		4,267			—			4,267
Costs incurred		(6,945	)		—			(6,945	)
Foreign currency impact and other		116			—			116

Balance at March 31, 2011	$	4,920		$	—		$	4,920
Accrual adjustment		(681	)		—			(681	)
Accrued		4,958			—			4,958
Costs incurred		(7,966	)		—			(7,966	)
Foreign currency impact and other		(45	)		—			(45	)


Balance at March 31, 2012	$	1,186		$	—		$	1,186

Warranty (Tables)

12 Months Ended

Mar. 31, 2012

Warranty [Abstract]

Analysis Of Changes In Liability For Product Warranties


Balance at March 31, 2009	$	30,914
Current year provisions		13,123
Costs incurred		(13,283	)
Foreign exchange and other		985

Balance at March 31, 2010	$	31,739
Current year provisions		20,565
Costs incurred		(17,499	)
Foreign exchange and other		1,201

Balance at March 31, 2011	$	36,006
Current year provisions		26,841
Costs incurred		(20,185	)
Foreign exchange and other		(595	)

Balance at March 31, 2012	$	42,067

Other (Income) Expense, Net And Charges Related To Refinancing (Tables)

12 Months Ended

Mar. 31, 2012

Other (Income) Expense, Net And Charges Related To Refinancing [Abstract]

Summary Of Other (Income) Expense, Net


	Fiscal Years Ended March 31,
	2012		2011		2010
Foreign exchange transaction losses	$	1,483	$	732	$	3,045
Secondary offering fees		—		615		150
Other		1,585		830		1,189

Total	$	3,068	$	2,177	$	4,384

Summary Of Charges Related To Refinancing


	Fiscal Years Ended March 31,
	2012		2011		2010
Charges related to refinancing	$	—	$	8,155	$	—

Operations By Industry Segment And Geographic Area (Tables)

12 Months Ended

Mar. 31, 2012

Operations By Industry Segment And Geographic Area [Abstract]

Summary Of Financial Information Related To The Company's Business Segments


	Fiscal Years Ended March 31,
	2012			2011			2010
Net sales by segment to unaffiliated customers
Europe	$	995,431		$	890,313		$	741,975
Americas		1,082,747			896,629			700,297
Asia		205,191			177,520			137,113

Total net sales	$	2,283,369		$	1,964,462		$	1,579,385

Net sales by product line
Reserve power	$	1,092,734		$	970,480		$	820,526
Motive power		1,190,635			993,982			758,859

Total net sales	$	2,283,369		$	1,964,462		$	1,579,385

Intersegment sales
Europe	$	75,652		$	55,586		$	37,449
Americas		38,115			42,141			24,848
Asia		21,182			21,349			13,237

Total intersegment sales⁽¹⁾	$	134,949		$	119,076		$	75,534

Operating earnings
Europe	$	63,872		$	55,643		$	17,649
Americas		138,894			124,515			87,156
Asia		12,133			10,469			20,502
Legal proceedings settlement income (Europe)		900			—			—
Restructuring charges (Europe)		(4,988	)		(6,813	)		(13,212	)
Restructuring charges (Americas)		—			—			(717	)
Bargain purchase gain (Europe)		—			—			2,919

Total operating earnings⁽²⁾	$	210,811		$	183,814		$	114,297

Property, plant and equipment, net
Europe	$	161,854		$	169,056		$	156,953
Americas		144,701			142,263			138,217
Asia		46,660			33,066			19,971

Total	$	353,215		$	344,385		$	315,141

Capital Expenditures
Europe	$	21,631		$	22,034		$	20,624
Americas		20,862			22,368			21,089
Asia		6,450			15,538			3,398

Total	$	48,943		$	59,940		$	45,111

Depreciation and Amortization
Europe	$	25,451		$	21,564		$	22,348
Americas		21,466			19,842			19,189
Asia		3,443			2,987			3,314

Total	$	50,360		$	44,393		$	44,851

(1)

Intersegment sales are presented on a cost plus basis which takes into consideration the effect of transfer prices between legal entities.

(2)

The Company does not allocate interest expense or other (income) expense to the reportable segments.

Tabular disclosure of the profit or loss and total assets for each reportable segment. An entity discloses certain information on each reportable segment if the amounts (a) are included in the measure of segment profit or loss reviewed by the chief operating decision maker or (b) are otherwise regularly provided to the chief operating decision maker, even if not included in that measure of segment profit or loss.

Summary Of Interim Financial Information

Quarterly Financial Data (Tables)

12 Months Ended

Mar. 31, 2012

Quarterly Financial Data [Abstract]


	1st Quarter		2nd Quarter		3rd Quarter		4th Quarter		Fiscal Year
Fiscal year ended March 31, 2012
Net sales	$	569,229	$	547,140	$	574,246	$	592,754	$	2,283,369
Gross profit		121,971		114,395		130,876		145,463		512,705
Operating earnings⁽¹⁾		48,715		42,440		53,777		65,879		210,811
Net earnings		33,496		28,289		36,859		45,323		143,967
Net earnings attributable to EnerSys stockholders		33,496		28,289		36,859		45,359		144,003
Net earnings per common share attributable to EnerSys stockholders—basic	$	0.67	$	0.57	$	0.77	$	0.95	$	2.95
Net earnings per common share attributable to EnerSys stockholders—diluted	$	0.66	$	0.57	$	0.77	$	0.94	$	2.93


Fiscal year ended March 31, 2011
Net sales	$	434,969	$	472,843	$	508,596	$	548,054	$	1,964,462
Gross profit		96,614		110,721		117,900		124,609		449,844
Operating earnings⁽²⁾		37,480		44,496		48,320		53,518		183,814
Net earnings⁽³⁾		23,027		26,549		33,759		30,091		113,426
Net earnings attributable to EnerSys stockholders		23,027		26,549		33,759		30,091		113,426
Net earnings per common share attributable to EnerSys stockholders—basic	$	0.47	$	0.54	$	0.68	$	0.60	$	2.30
Net earnings per common share attributable to EnerSys stockholders—diluted	$	0.47	$	0.53	$	0.67	$	0.59	$	2.27

(1)

(2)

Included in Operating earnings were restructuring charges of $723, $2,750, $1,754 and $1,586 for the first, second, third and fourth quarters of fiscal 2011, respectively.

(3)

Included in Net earnings of fiscal 2011 were charges related to refinancing of $8,155 in the fourth quarter of fiscal 2011.

Summary Of Significant Accounting Policies (Details) ₨ in Thousands, ¥ in Thousands, $ in Thousands	12 Months Ended
	Mar. 31, 2012 INR (₨) yr shares	Mar. 31, 2012 CNY (¥)	Mar. 31, 2012 USD ($)	Mar. 31, 2011 CNY (¥)	Mar. 31, 2011 USD ($)	Mar. 29, 2011 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives of finite-lived assets, minimum (in years)	3
Estimated useful lives of finite-lived assets, maximum (in years)	20
Convertible Notes \| $			$ 172,500
Buildings And Improvements [Member]
Summary Of Significant Accounting Policies [Line Items]
Property, plant, and equipment, useful life, minimum (in years)	10
Property, plant, and equipment, useful life, maximum (in years)	33
Machinery And Equipment [Member]
Summary Of Significant Accounting Policies [Line Items]
Property, plant, and equipment, useful life, minimum (in years)	3
Property, plant, and equipment, useful life, maximum (in years)	15
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Market share units converted into common stock for each unit \| shares	2
Maximum [Member] \| Reserve Power Batteries [Member]
Summary Of Significant Accounting Policies [Line Items]
Product warranty for a period	20 years
Maximum [Member] \| Motive Power Batteries [Member]
Summary Of Significant Accounting Policies [Line Items]
Product warranty for a period	7 years
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Recognizes the largest amount of the benefit that is greater realized upon ultimate settlement, percentage	50.00%
Market share units converted into common stock for each unit \| shares	0
Minimum [Member] \| Reserve Power Batteries [Member]
Summary Of Significant Accounting Policies [Line Items]
Product warranty for a period	1 year
Minimum [Member] \| Motive Power Batteries [Member]
Summary Of Significant Accounting Policies [Line Items]
Product warranty for a period	1 year
Restricted Stock And Restricted Stock Units [Member]
Summary Of Significant Accounting Policies [Line Items]
Percentage of restricted stock units granted, vested per year	25.00%
Vesting period, in years	4 years
2011 Senior Secured Revolving Credit Facility [Member]
Summary Of Significant Accounting Policies [Line Items]
Fair value of Company's new senior secured revolving credit facility \| $			$ 350,000			$ 350,000
China Term Loan [Member]
Summary Of Significant Accounting Policies [Line Items]
Fair value of Company's new senior secured revolving credit facility		¥ 75,000		¥ 75,000	$ 11,909
Interest rate of debt instrument	7.26%	7.26%	7.26%
Senior Unsecured 3.375% Convertible Notes Due 2038 [Member]
Summary Of Significant Accounting Policies [Line Items]
Interest rate of debt instrument	3.375%	3.375%	3.375%
Convertible Notes \| $			$ 172,500
India Term Loan [Member]
Summary Of Significant Accounting Policies [Line Items]
Fair value of Company's new senior secured revolving credit facility \| ₨	₨ 273,780
Interest rate of debt instrument	15.10%	15.10%	15.10%

Acquisitions (Details) $ in Thousands		1 Months Ended	12 Months Ended
Acquisitions (Details) $ in Thousands	Feb. 28, 2011 USD ($)	Nov. 30, 2009 USD ($)	Mar. 31, 2012 USD ($)	Mar. 31, 2011 USD ($)	Mar. 31, 2010 USD ($)
Business Acquisition [Line Items]
Number of acquisitions			4
Combined net purchase price			$ 24,553
Goodwill relating to acquisitions			10,723	$ 15,301
Bargain purchase gain					$ 2,919
Trademarks [Member]
Business Acquisition [Line Items]
Acquired intangible assets			2,000
Customer Relationships [Member]
Business Acquisition [Line Items]
Non-compete agreements			500
Acquired intangible assets			3,400
Technology [Member]
Business Acquisition [Line Items]
Acquired intangible assets			$ 4,265
ABSL Power Solutions Ltd [Member]
Business Acquisition [Line Items]
Combined net purchase price	$ 32,200
Goodwill relating to acquisitions	15,342
ABSL Power Solutions Ltd [Member] \| Trademarks [Member]
Business Acquisition [Line Items]
Acquired intangible assets	1,774
ABSL Power Solutions Ltd [Member] \| Customer Relationships [Member]
Business Acquisition [Line Items]
Acquired intangible assets	3,547
ABSL Power Solutions Ltd [Member] \| Technology [Member]
Business Acquisition [Line Items]
Acquired intangible assets	$ 2,741
Oerlikon [Member]
Business Acquisition [Line Items]
Combined net purchase price		$ 33,242
Bargain purchase gain		$ 2,919

Inventories (Narrative) (Details) - USD ($) $ in Thousands	Mar. 31, 2012	Mar. 31, 2011
Inventories [Abstract]
Inventory reserves for obsolescence and other estimated losses	$ 14,831	$ 15,052

The amount of the valuation account as of the balance sheet date which reduces the carrying amount of inventory to net realizable value; takes into consideration such factors as market value, excessive quantities based on expected sales, technological obsolescence, and shrinkage. May also provide for estimated product returns or price concessions pertaining to product cost.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 6
-Subparagraph a
-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 43
-Chapter 3
-Section A
-Paragraph 9
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 43
-Chapter 4
-Paragraph 14
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 43
-Chapter 4
-Paragraph 8, 9, 14
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 09
-Article 12

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.6(a))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 330
-SubTopic 10
-Section 35
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6386567&loc=d3e3927-108312

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 330
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB TOPIC 5.BB)
-URI http://asc.fasb.org/extlink&oid=6386940&loc=d3e100047-122729

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SX 210.12-09)
-URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e24092-122690

Inventories (Summary Of Net Inventories) (Details) - USD ($) $ in Thousands	Mar. 31, 2012	Mar. 31, 2011
Inventories [Abstract]
Raw materials	$ 100,538	$ 92,928
Work-in-process	111,629	100,261
Finished goods	149,607	141,814
Total	$ 361,774	$ 335,003

Property, Plant, And Equipment (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
Property, Plant, And Equipment [Abstract]
Depreciation expense	$ 48,532	$ 43,517	$ 44,145
Interest capitalized	$ 797	$ 1,292	$ 929

Property, Plant, And Equipment (Summary Of Property, Plant, And Equipment) (Details) - USD ($) $ in Thousands	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
Property, Plant, And Equipment [Abstract]
Land, buildings, and improvements	$ 201,038	$ 174,887
Machinery and equipment	511,599	475,818
Construction in progress	29,779	51,662
Gross	742,416	702,367
Less accumulated depreciation	(389,201)	(357,982)
Total	$ 353,215	$ 344,385	$ 315,141

The cumulative amount of depreciation, depletion and amortization (related to property, plant and equipment, but not including land) that has been recognized in the income statement.

Goodwill And Other Intangible Assets (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
Goodwill And Other Intangible Assets [Abstract]
Amortization expense, related to finite-lived intangible assets	$ 1,828	$ 876	$ 706
Expected amortization expense, 2013	2,463
Expected amortization expense, 2014	2,238
Expected amortization expense, 2015	2,124
Expected amortization expense, 2016	2,092
Expected amortization expense, 2017	1,966
Estimated tax-deductible goodwill	$ 12,745	$ 14,982

The amount of goodwill arising from a business combination that is expected to be deductible for tax purposes.

Goodwill And Other Intangible Assets (Schedule Of Company's Other Intangible Assets) (Details) - USD ($) $ in Thousands	Mar. 31, 2012	Mar. 31, 2011
Intangible Assets [Line Items]
Gross Amount, Total	$ 113,550	$ 103,457
Accumulated Amortization, Total	(6,468)	(4,638)
Net Amount, Total	107,082	98,819
Customer Relationships [Member]
Intangible Assets [Line Items]
Finite-lived intangible assets, Gross Amount	14,330	11,064
Finite-lived intangible assets, Accumulated Amortization	(2,839)	(1,880)
Finite-lived intangible assets, Net Amount	11,491	9,184
Non-Compete [Member]
Intangible Assets [Line Items]
Finite-lived intangible assets, Gross Amount	2,602	2,117
Finite-lived intangible assets, Accumulated Amortization	(1,224)	(954)
Finite-lived intangible assets, Net Amount	1,378	1,163
Patents [Member]
Intangible Assets [Line Items]
Finite-lived intangible assets, Gross Amount	5,230	3,402
Finite-lived intangible assets, Accumulated Amortization	(615)	(210)
Finite-lived intangible assets, Net Amount	4,615	3,192
Trademarks [Member]
Intangible Assets [Line Items]
Finite-lived intangible assets, Gross Amount	2,003	3,771
Finite-lived intangible assets, Accumulated Amortization	(643)	(559)
Finite-lived intangible assets, Net Amount	1,360	3,212
Licenses [Member]
Intangible Assets [Line Items]
Finite-lived intangible assets, Gross Amount	2,640	82
Finite-lived intangible assets, Accumulated Amortization	(194)	(82)
Finite-lived intangible assets, Net Amount	2,446
Trademarks [Member]
Intangible Assets [Line Items]
Indefinite-lived intangible assets, Gross Amount	86,745	83,021
Indefinite-lived intangible assets, Accumulated Amortization	(953)	(953)
Indefinite-lived intangible assets, Net Amount	$ 85,792	$ 82,068

Goodwill And Other Intangible Assets (Schedule Of Changes In The Carrying Amount Of Goodwill By Business Segment) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Goodwill [Line Items]
Balance at beginning of year	$ 343,666	$ 317,265
Goodwill acquired during the year	10,723	15,301
Adjustments related to the finalization of purchase accounting for prior year acquisitions	379	2,274
Foreign currency translation	(7,707)	8,826
Balance at end of year	347,061	343,666
Europe [Member]
Goodwill [Line Items]
Balance at beginning of year	177,881	162,641
Goodwill acquired during the year	1,250	7,710
Adjustments related to the finalization of purchase accounting for prior year acquisitions	374	24
Foreign currency translation	(7,977)	7,506
Balance at end of year	171,528	177,881
Americas [Member]
Goodwill [Line Items]
Balance at beginning of year	143,225	132,915
Goodwill acquired during the year	7,973	7,591
Adjustments related to the finalization of purchase accounting for prior year acquisitions	5	2,250
Foreign currency translation	(449)	469
Balance at end of year	150,754	143,225
Asia [Member]
Goodwill [Line Items]
Balance at beginning of year	22,560	21,709
Goodwill acquired during the year	1,500
Foreign currency translation	719	851
Balance at end of year	$ 24,779	$ 22,560

Carrying amount as of the balance sheet date, which is the cumulative amount paid and (if applicable) the fair value of any noncontrolling interest in the acquiree, adjusted for any amortization recognized prior to the adoption of any changes in generally accepted accounting principles (as applicable) and for any impairment charges, in excess of the fair value of net assets acquired in one or more business combination transactions.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 142
-Paragraph 45
-Subparagraph e
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 142
-Paragraph 43
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 141R
-Paragraph 68
-Subparagraph l
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6905597&loc=d3e13816-109267

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 141R
-Paragraph 72
-Subparagraph d
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 142
-Paragraph 45
-Subparagraph e
-Clause 1
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 141R
-Paragraph 34
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Prepaid And Other Current Assets (Schedule Of Prepaid And Other Current Assets) (Details) - USD ($) $ in Thousands	Mar. 31, 2012	Mar. 31, 2011
Prepaid And Other Current Assets [Abstract]
Prepaid non income taxes	$ 23,737	$ 22,753
Non-trade receivables	8,247	8,214
Prepaid income taxes	7,716	15,986
Lead hedges		9,575
Other	12,693	13,675
Total	$ 52,393	$ 70,203

Accrued Expenses (Summary Of Accrued Expenses) (Details) - USD ($) $ in Thousands	Mar. 31, 2012	Mar. 31, 2011
Accrued Expenses [Abstract]
Payroll and benefits	$ 55,595	$ 58,794
Accrued selling expenses	26,269	24,257
Warranty	19,274	16,218
Income taxes payable	16,979	15,591
VAT and other non-income taxes	10,966	11,937
Freight	12,314	10,208
Deferred income	12,057	7,107
Interest rate swaps	3,628
Interest	2,040	2,471
Pension and social security	1,696	1,854
Restructuring	1,186	5,323
Other	26,399	30,940
Total	$ 188,403	$ 184,700

Debt (2011 Senior Secured Revolving Credit Facility) (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2012	Mar. 29, 2011
Debt Instrument [Line Items]
Senior secured revolving credit facility, initiation date	March 29, 2011
Liquidity test required to be met	February 2015
Capacity to meet potential obligations related to Convertible Notes	June 2015
Company owned capital stock percentage	65.00%
2011 Senior Secured Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 350,000	$ 350,000
Maturity date	Mar. 31, 2016
Secured Credit Facility [Member]
Debt Instrument [Line Items]
Interest rate of debt instrument	1.60%
Option One [Member] \| 2011 Senior Secured Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Interest on borrowings at a floating rate	LIBOR plus an applicable percentage (currently <font class="_mt">1.25</font>%)
Option Two [Member] \| 2011 Senior Secured Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Interest on borrowings at a floating rate	the greater of the Federal Funds rate plus <font class="_mt">0.50</font>% or the prime rate, or one-month LIBOR plus <font class="_mt">1.0</font>%, plus an applicable percentage (currently <font class="_mt">0.25</font>%)
LIBOR Rate [Member] \| Option One [Member] \| Applicable Percentage [Member]
Debt Instrument [Line Items]
Interest at a floating rate	1.25%
LIBOR Rate [Member] \| Option Two [Member]
Debt Instrument [Line Items]
Interest at a floating rate	1.00%
LIBOR Rate [Member] \| Option Two [Member] \| Applicable Percentage [Member]
Debt Instrument [Line Items]
Interest at a floating rate	0.50%
Federal Funds Rate [Member] \| Option Two [Member]
Debt Instrument [Line Items]
Interest at a floating rate	0.25%

Debt (China Term Loan) (Narrative) (Details) - China Term Loan [Member] ¥ in Thousands, $ in Thousands	12 Months Ended
	Mar. 31, 2012 CNY (¥) yr	Mar. 31, 2012 USD ($) yr	Mar. 31, 2012 USD ($)	Mar. 31, 2011 CNY (¥)	Mar. 31, 2011 USD ($)
Debt Instrument [Line Items]
Maximum borrowing capacity	¥ 75,000			¥ 75,000	$ 11,909
Debt drawn amount	¥ 38,000		$ 6,034
Term loan (in years)	6	6
Interest rate of debt instrument	7.26%		7.26%
Quarterly installments	¥ 2,000	$ 318

Debt (India Term Loan) (Narrative) (Details) - India Term Loan [Member] ₨ in Thousands, $ in Thousands	12 Months Ended
	Mar. 31, 2012 INR (₨)	Mar. 31, 2012 USD ($)	Mar. 31, 2012 USD ($)
Debt Instrument [Line Items]
Syndicated term loan	₨ 273,780		$ 5,383
Interest rate of debt instrument	15.10%		15.10%
Interest rate adjustment period	2 years	2 years
Quarterly installments	₨ 15,000	$ 295
Duration of payments	5 years	5 years

Debt (Senior Unsecured 3.375% Convertible Notes) (Narrative) (Details)		12 Months Ended
	May 28, 2008 USD ($)	Mar. 31, 2012 USD ($) mo $ / shares shares	Mar. 31, 2011 USD ($)	Mar. 31, 2010 USD ($)
Convertible Notes [Member]
Debt Instrument [Line Items]
Face value of debt instrument	$ 172,500	$ 172,500
Interest rate of debt instrument		3.375%
Debt instrument maturity year		2038
Net proceeds received after deduction of commissions and offering expenses	$ 168,200,000
Semi-annual payment of interest in arrears		June 1 and December 1
Maturity date of Convertible Notes		Jun. 01, 2038
Initial conversion rate \| shares		24.6305
Principal amount of Convertible Notes		$ 1,000
Conversion price per share \| $ / shares		$ 40.60
Redemption price percentage of debt instrument of accreted principal amount		100.00%
Minimum price of Common Stock per share for eligibility of make-whole premium payment \| $ / shares		$ 29.00
Aggregate consideration on conversion shares \| shares		4,248,761
Interest rate percentage		8.50%
Amount of interest cost recognized for the amortization of the discount		$ 6,435,000	$ 5,917,000	$ 5,439,000
Available lines of credit		377,230,000	356,447,000
Outstanding amount		95,340,000	95,049,000
Convertible Notes discount		24,228,000	30,663,000
Standby letters of credit		$ 9,108,000	1,150,000
Senior Unsecured 3.375% Convertible Notes Due 2038 [Member]
Debt Instrument [Line Items]
Interest rate of debt instrument		3.375%
Debt instrument maturity year		2038
Amortized remaining discount period, in months \| mo		38
Interest paid		$ 8,933,000	$ 16,101,000	$ 16,456,000

Debt (Deferred Financing Fees) (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
Debt [Abstract]
Write-off of unamortized deferred financing fees		$ 2,308
New deferred financing fees		3,500
Deferred financing fees, net of accumulated amortization	$ 4,634	5,912
Amortization expense included in interest expense	$ 1,278	$ 1,861	$ 1,724

Debt (Schedule Of Long-Term Debt) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Debt Instrument [Line Items]
Long-term debt	$ 239,129	$ 247,992
Less current portion	2,540	43
Long-term Debt, Excluding Current Maturities	236,589	247,949
Senior Unsecured 3.375% Convertible Notes Due 2038 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 148,272	141,837
Interest rate of debt instrument	3.375%
Maturity year	2038
2011 Credit Facility Due 2016 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 79,400	100,000
Maturity year	2016
China Term Loan [Member]
Debt Instrument [Line Items]
Long-term debt	$ 6,034	6,112
Interest rate of debt instrument	7.26%
Maturity year	2017
India Term Loan [Member]
Debt Instrument [Line Items]
Long-term debt	$ 5,383
Interest rate of debt instrument	15.10%
Maturity year	2017
Other [Member]
Debt Instrument [Line Items]
Long-term debt	$ 40	$ 43

Debt (Components Of Net Carrying Amount Of Convertible Notes) (Details) - USD ($) $ in Thousands	Mar. 31, 2012	Mar. 31, 2011
Debt Instrument [Line Items]
Net carrying amount	$ 239,129	$ 247,992
Convertible Notes [Member]
Debt Instrument [Line Items]
Principal	172,500	172,500
Unamortized discount	(24,228)	(30,663)
Net carrying amount	148,272	141,837
Carrying amount of equity component	$ 29,850	$ 29,850

Debt (Summary Of Aggregate Maturities Of Long-Term Debt) (Details) $ in Thousands	Mar. 31, 2012 USD ($)
Debt [Abstract]
2013	$ 2,540
2014	2,450
2015	2,450
2016	254,350
2017	1,567
Thereafter
Net carrying amount	$ 263,357

Leases (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
Leases (Narrative) (Details) - USD ($) $ in Thousands	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
Leases [Abstract]
Rental expense	$ 31,619	$ 28,047	$ 26,957

Leases (Schedule Of Capital And Operating Leases) (Details) - USD ($) $ in Thousands	Mar. 31, 2012	Mar. 31, 2011
Leases [Abstract]
2013, Operating Leases	$ 18,268
2014, Operating Leases	13,478
2015, Operating Leases	10,108
2016, Operating Leases	6,981
2017, Operating Leases	5,008
Thereafter, Operating Leases	3,588
Total minimum lease payments, Operating Leases	57,431
2013, Capital Leases	451
2014, Capital Leases	475
2015, Capital Leases	84
2016, Capital Leases	14
2017, Capital Leases	7
Thereafter, Capital Leases
Total minimum lease payments, Capital Leases	1,031
Amounts representing interest	101
Net minimum lease payments, including current portion	930
Net minimum lease payments, current portion	$ 409	$ 819

Other Liabilities (Schedule Of Other Long-Term Liabilities) (Details) - USD ($) $ in Thousands	Mar. 31, 2012	Mar. 31, 2011
Other Liabilities [Abstract]
Pension and profit sharing obligation	$ 35,804	$ 29,297
Warranty	22,793	19,788
Long-term income taxes liabilities	13,520	11,320
Deferred income	6,094	3,839
Interest rate swap liabilities	244	5,847
Other	14,013	6,552
Total	$ 92,468	$ 76,643

This represents the noncurrent liability recognized in the balance sheet that is associated with the defined benefit pension plans and other postretirement and postemployment benefit plans.

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Fair Value Of Financial Instruments (Narrative) (Details) - Convertible Notes [Member] - USD ($)	12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Face value of debt instrument	$ 172,500	$ 172,500
Price of stock per share when Convertible Notes were issued	$ 30.19
Closing price of stock	34.65
Conversion option price per share	$ 40.60
Trading of Convertible Notes, face value, disclosed as a percentage	116.00%	125.00%
Unamortized discount	$ 24,228,000	$ 30,663,000

Fair Value Of Financial Instruments (Financial Assets And (Liabilities), Measured At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Thousands	Mar. 31, 2012	Mar. 31, 2011
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total derivatives	$ (3,941)	$ 1,137
Quoted Price In Active Markets For Identical Assets (Level 1) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total derivatives
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total derivatives	(3,941)	1,137
Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total derivatives
Interest Rate Swap Agreements [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total derivatives	(3,872)	(5,847)
Interest Rate Swap Agreements [Member] \| Quoted Price In Active Markets For Identical Assets (Level 1) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total derivatives
Interest Rate Swap Agreements [Member] \| Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total derivatives	(3,872)	(5,847)
Interest Rate Swap Agreements [Member] \| Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total derivatives
Lead Hedge Forward Contracts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total derivatives	(851)	9,575
Lead Hedge Forward Contracts [Member] \| Quoted Price In Active Markets For Identical Assets (Level 1) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total derivatives
Lead Hedge Forward Contracts [Member] \| Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total derivatives	(851)	9,575
Lead Hedge Forward Contracts [Member] \| Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total derivatives
Foreign Currency Forward Contracts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total derivatives	782	(2,591)
Foreign Currency Forward Contracts [Member] \| Quoted Price In Active Markets For Identical Assets (Level 1) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total derivatives
Foreign Currency Forward Contracts [Member] \| Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total derivatives	782	(2,591)
Foreign Currency Forward Contracts [Member] \| Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total derivatives

Fair Value Of Financial Instruments (Carrying Amounts And Estimated Fair Values Of Company's Financial Instruments) (Details) - USD ($)

Mar. 31, 2012

Mar. 31, 2011

Derivatives assets, Carrying Amount

^[1]

$ 782,000

$ 9,575,000

Derivatives liabilities, Carrying Amount

^[1]

782,000

9,575,000

^[1]

4,723,000

8,438,000

Convertible Notes [Member]

^[1]

4,723,000

8,438,000

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Convertible Notes, Carrying Amount

^[2]

148,272,000

141,837,000

Convertible Notes, Fair Value

^[3]

200,100,000

215,625,000

Face value of debt instrument

$ 172,500

[1]	Represents interest rate swap agreements, lead and foreign currency hedges (see Note 12 for asset and liability positions of the interest rate swap agreements, lead and foreign currency hedges at March 31, 2012 and March 31, 2011).
[2]	The carrying amounts of the Convertible Notes at March 31, 2012 and March 31, 2011 represent the $172,500 principal value, less the unamortized debt discount (see Note 8).
[3]	The fair value amounts of the Convertible Notes represent the trading values of the Convertible Notes with a principal value of $172,500 at March 31, 2012 and March 31, 2011.

Derivative Financial Instruments (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Derivatives, Fair Value [Line Items]
Foreign currency forward contracts	$ 42,121	$ 71,930
Lead Hedge Forward Contracts [Member]
Derivatives, Fair Value [Line Items]
Notional amount	60,000	63,400
Cost Of Goods Sold [Member] \| Foreign Currency Forward Contracts [Member]
Derivatives, Fair Value [Line Items]
Pretax gain reclassified from accumulated other comprehensive income	1,784
Not Designated As Hedging Instrument [Member] \| Interest Rate Swap Agreements [Member]
Derivatives, Fair Value [Line Items]
Change in fair value recorded in other expense, net	977
Interest rate swap agreements converted into fixed rate basis	85,000	$ 85,000
Not Designated As Hedging Instrument [Member] \| Foreign Currency Forward Contracts [Member]
Derivatives, Fair Value [Line Items]
Notional amount	11,410
Change in fair value recorded in other expense, net	$ 106
Not Designated As Hedging Instrument [Member] \| Minimum [Member] \| Interest Rate Swap Agreements [Member]
Derivatives, Fair Value [Line Items]
Derivative, maturity date	Feb. 01, 2013
Not Designated As Hedging Instrument [Member] \| Maximum [Member] \| Interest Rate Swap Agreements [Member]
Derivatives, Fair Value [Line Items]
Derivative, maturity date	May 01, 2013

Derivative Financial Instruments (Fair Value Of Derivative Instruments In The Consolidated Balance Sheets) (Details) - USD ($)
$ in Thousands

Mar. 31, 2012

Mar. 31, 2011

^[1]

$ 782

$ 9,575

Designated As Hedging Instrument [Member]

^[1]

4,723

8,438

700

9,575

Designated As Hedging Instrument [Member] | Prepaid And Other Current Assets [Member] | Lead Hedge Forward Contracts [Member]

881

2,591

Designated As Hedging Instrument [Member] | Prepaid And Other Current Assets [Member] | Foreign Currency Forward Contracts [Member]

9,575

Designated As Hedging Instrument [Member] | Prepaid And Other Current Assets [Member] | Other Assets [Member]

670

Designated As Hedging Instrument [Member] | Accrued Expenses [Member] | Lead Hedge Forward Contracts [Member]

Designated As Hedging Instrument [Member] | Accrued Expenses [Member] | Foreign Currency Forward Contracts [Member]

881

Not Designated As Hedging Instrument [Member]

2,591

112

Not Designated As Hedging Instrument [Member] | Prepaid And Other Current Assets [Member] | Lead Hedge Forward Contracts [Member]

3,872

5,847

Not Designated As Hedging Instrument [Member] | Prepaid And Other Current Assets [Member] | Foreign Currency Forward Contracts [Member]

Not Designated As Hedging Instrument [Member] | Prepaid And Other Current Assets [Member] | Other Assets [Member]

112

Not Designated As Hedging Instrument [Member] | Accrued Expenses [Member] | Lead Hedge Forward Contracts [Member]

Not Designated As Hedging Instrument [Member] | Accrued Expenses [Member] | Foreign Currency Forward Contracts [Member]

Not Designated As Hedging Instrument [Member] | Accrued Expenses [Member] | Interest Rate Swap Agreements [Member]

Not Designated As Hedging Instrument [Member] | Other Liabilities [Member] | Interest Rate Swap Agreements [Member]

3,628

$ 244

$ 5,847

[1]	Represents interest rate swap agreements, lead and foreign currency hedges (see Note 12 for asset and liability positions of the interest rate swap agreements, lead and foreign currency hedges at March 31, 2012 and March 31, 2011).

Derivative Financial Instruments (The Effect Of Derivative Instruments On The Consolidated Statements Of Income) (Details) - Designated As Hedging Instrument [Member] - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
Derivatives, Fair Value [Line Items]
Gain (Loss) Recognized in AOCI on Derivative (Effective Portion)	$ (9,883)	$ 9,064	$ 9,382
Gain (Loss) Reclassified from AOCI into Income (Effective Portion)	(4,713)	190	5,342
Foreign Currency Forward Contracts [Member]
Derivatives, Fair Value [Line Items]
Gain (Loss) Recognized in AOCI on Derivative (Effective Portion)	(152)	(4,031)	2,679
Lead Hedge Forward Contracts [Member]
Derivatives, Fair Value [Line Items]
Gain (Loss) Recognized in AOCI on Derivative (Effective Portion)	(9,731)	15,930	9,844
Interest Rate Swap Contracts [Member]
Derivatives, Fair Value [Line Items]
Gain (Loss) Recognized in AOCI on Derivative (Effective Portion)		(2,835)	(3,141)
Interest Expense [Member] \| Interest Rate Swap Contracts [Member]
Derivatives, Fair Value [Line Items]
Gain (Loss) Reclassified from AOCI into Income (Effective Portion)		(6,698)	(7,059)
Cost Of Goods Sold [Member] \| Foreign Currency Forward Contracts [Member]
Derivatives, Fair Value [Line Items]
Gain (Loss) Reclassified from AOCI into Income (Effective Portion)	(3,882)	471	428
Cost Of Goods Sold [Member] \| Lead Hedge Forward Contracts [Member]
Derivatives, Fair Value [Line Items]
Gain (Loss) Reclassified from AOCI into Income (Effective Portion)	$ (831)	$ 6,417	$ 11,973

Derivative Financial Instruments (Effect Of Derivative Instruments) (Details) - Not Designated As Hedging Instrument [Member] - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Derivatives, Fair Value [Line Items]
Location of Gain (Loss) Recognized in Income on Derivative	$ (1,083)	$ (5,847)
Charges Related To Refinancing [Member] \| Interest Rate Swap Contracts [Member]
Derivatives, Fair Value [Line Items]
Location of Gain (Loss) Recognized in Income on Derivative		$ (5,847)
Other (Income) Expense [Member] \| Interest Rate Swap Contracts [Member]
Derivatives, Fair Value [Line Items]
Location of Gain (Loss) Recognized in Income on Derivative	(977)
Other (Income) Expense [Member] \| Foreign Currency Forward Contracts [Member]
Derivatives, Fair Value [Line Items]
Location of Gain (Loss) Recognized in Income on Derivative	$ (106)

The amount of net gains and losses recognized in income during the period on derivative instruments designated and qualifying as hedging instruments in fair value hedges and related hedged items designated and qualifying in fair value hedges, on derivative instruments designated and qualifying as hedging instruments in cash flow hedges, and on derivative instruments not designated as hedging instruments.

Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
Operating Loss Carryforwards [Line Items]
Income taxes paid	$ 38,482	$ 41,800	$ 22,553
United States federal net operating loss carryforwards	11,139
Limited by Internal Revenue Code	$ 3,375
Operating loss carryforwards, expiration date	2023
Valuation allowance	$ 793	5,432
Net operating loss carryforwards foreign subsidiaries	$ 235,000
Operating loss carryforwards, life period, years	20 years
Net operating loss carryforwards for state tax purposes	$ 45,559
Tax benefit	47,292	$ 38,018	$ 24,951
Decrease deferred tax assets operating loss carry forwards	$ 2,162
Net operating loss carryforwards, state expiration period, years	20 years
Effective income tax rates	24.70%	25.10%	28.60%
Tax benefits due to the utilization of net operating loss carryforwards	$ 2,940	$ 2,498
Undistributed earnings of foreign subsidiaries	$ 494,000
Balance of unrecognized tax benefits recognized, period	12 months
Tax related interest and penalties	$ 575	675
Domestic [Member]
Operating Loss Carryforwards [Line Items]
Tax benefit	2,477
Foreign [Member]
Operating Loss Carryforwards [Line Items]
Valuation allowance associated with certain foreign and state tax jurisdictions	53,206	55,738
State [Member]
Operating Loss Carryforwards [Line Items]
Valuation allowance associated with certain foreign and state tax jurisdictions	$ 2,360	$ 2,447

Income Taxes (Income Tax Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
Income Taxes [Abstract]
Federal, Current	$ 30,459	$ 24,232	$ 9,000
State, Current	3,778	2,736	(981)
Foreign, Current	16,282	14,114	9,957
Total current	50,519	41,082	17,976
Federal, Deferred	(1,609)	(1,358)	4,678
State, Deferred	(962)	2,010	852
Foreign, Deferred	(656)	(3,716)	1,445
Total deferred	(3,227)	(3,064)	6,975
Income tax expense	$ 47,292	$ 38,018	$ 24,951

Income Taxes (Earnings Before Income Taxes) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
Income Taxes [Abstract]
United States	$ 87,597	$ 57,710	$ 37,418
Foreign	103,662	93,734	49,837
Earnings before income taxes	$ 191,259	$ 151,444	$ 87,255

Income Taxes (Deferred Tax Assets And Liabilities) (Details) - USD ($) $ in Thousands	Mar. 31, 2012	Mar. 31, 2011
Income Taxes [Abstract]
Accounts receivable	$ 1,111	$ 1,304
Inventories	6,707	6,669
Net operating loss carryforwards	71,773	78,236
Accrued liabilities	26,997	22,061
Other assets	10,228	9,200
Gross deferred tax assets	116,816	117,470
Less valuation allowance	(56,359)	(63,617)
Total deferred tax assets	60,457	53,853
Property, plant and equipment	30,957	31,945
Other intangible assets	46,628	43,440
Convertible Notes	21,616	20,727
Other liabilities	2,400	4,992
Total deferred tax liabilities	101,601	101,104
Net deferred tax liabilities	$ (41,144)	$ (47,251)

Income Taxes (Reconciliation Of Income Taxes At The Statutory Rate) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
Income Taxes [Abstract]
United States statutory income tax expense (at 35%)	$ 66,962	$ 53,005	$ 30,539
State income taxes, net of federal effect	1,592	3,035	(116)
Nondeductible expenses, domestic manufacturing deduction and other	1,587	(1,848)	3,799
Effect of foreign operations	(20,028)	(14,841)	(9,253)
Valuation allowance	(2,821)	(1,333)	(18)
Income tax expense	$ 47,292	$ 38,018	$ 24,951
United States statutory income tax expense rate percentage	35.00%

Income Taxes (Reconciliation Of Unrecognized Tax Benefits) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
Income Taxes [Abstract]
Unrecognized tax benefits, beginning balance	$ 10,645	$ 10,750	$ 13,305
Increases related to current year tax positions	5,032	2,896	919
Increases related to prior year tax positions due to foreign currency translation	(28)	122	5
Increases related to prior year tax positions	182	324
Decreases related to prior year tax position settled		(3,145)	(2,940)
Lapse of statute of limitations	(2,886)	(302)	(539)
Unrecognized tax benefits, ending balance	$ 12,945	$ 10,645	$ 10,750

Retirement Plans (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
Defined Benefit Plan Disclosure [Line Items]
Equity investments target range, minimum	50.00%
Equity investments target range, maximum	70.00%
Extended terms of return on portfolio investment, minimum	3 years
Extended terms of return on portfolio investment, maximum	5 years
Expected cash contributions to pension plans in 2013	$ 2,571
Germany And France Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation	$ 22,874	$ 21,706
First Percentage Of Wages Contribution [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of wages contributed for total match	4.00%
Next Percentage Of Wages Contribution [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of wages contributed for total match	2.00%
Defined Contribution Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer expenses	$ 5,146	$ 5,025	$ 3,909
Defined Contribution 401(k) Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Contribution description	All eligible employees of the amended 401(k) Plan receive a matching contribution of <font class="_mt">100</font>% of the first <font class="_mt">4</font>% of wages contributed and <font class="_mt">50</font>% of the next <font class="_mt">2</font>% of wages contributed for a total match of up to <font class="_mt">5</font>% by the Company.
Defined Contribution Amended U.K. Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Contribution description	Active members of the Amended U.K. Plan as of February 1, 2009 receive a matching contribution from the Company up to <font class="_mt">4</font>% of Pensionable Salary and an enhanced Company contribution in excess of this in line with the rules of the plan. New eligible employees of the Amended U.K. Plan receive a matching contribution from the Company up to <font class="_mt">5</font>% of pensionable salary, at various rates as provided by the plan.
Defined Contribution Amended U.K. Plan [Member] \| Pensionable Salary [Member]
Defined Benefit Plan Disclosure [Line Items]
Matching contribution	5.00%
Matching contribution received in excess of Pensionable Salary	4.00%
Defined Contribution, Amended 401(k) Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of total match up, by the company	5.00%
Defined Contribution, Amended 401(k) Plan [Member] \| First Percentage Of Wages Contribution [Member]
Defined Benefit Plan Disclosure [Line Items]
Matching contribution	100.00%
Defined Contribution, Amended 401(k) Plan [Member] \| Next Percentage Of Wages Contribution [Member]
Defined Benefit Plan Disclosure [Line Items]
Matching contribution	50.00%

Retirement Plans (Components Of Net Periodic Pension Cost) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
United States Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 285	$ 250	$ 224
Interest cost	668	646	635
Expected return on plan assets	(706)	(624)	(491)
Amortization and deferral	238	248	458
Net periodic benefit cost	485	520	826
International Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	645	603	621
Interest cost	2,504	2,503	2,520
Expected return on plan assets	(1,787)	(1,615)	(1,256)
Amortization and deferral	32	53	(43)
Net periodic benefit cost	$ 1,394	$ 1,544	$ 1,842

An amount calculated as a basis for determining the extent of delayed recognition of the effects of changes in the fair value of assets. The expected return on plan assets is determined based on the expected long-term rate of return on plan assets and the market-related value of plan assets.

The increase in a defined benefit pension plan's projected benefit obligation or a defined benefit postretirement plan's accumulated postretirement benefit obligation due to the passage of time.

The actuarial present value of benefits attributed by the pension benefit formula to services rendered by employees during the period. The portion of the expected postretirement benefit obligation attributed to employee service during the period. The service cost component is a portion of the benefit obligation and is unaffected by the funded status of the plan.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 106
-Paragraph 518
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 87
-Paragraph 264
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5
-Subparagraph a, h
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (h)(1)
-URI http://asc.fasb.org/extlink&oid=6962843&loc=d3e1928-114920

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=6962843&loc=d3e1928-114920

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Service Cost (Component of Net Periodic Pension Cost)
-URI http://asc.fasb.org/extlink&oid=6525008

Retirement Plans (Summary Of Change In Projected Benefit Obligation) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
United States Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation at the beginning of the period	$ 11,903	$ 10,992
Service cost	285	250	$ 224
Interest cost	668	646	635
Benefits paid, inclusive of plan expenses	(615)	(581)
Plan amendments		108
Experience (gain) loss	1,799	488
Benefit obligation at the end of the period	14,040	11,903	10,992
International Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation at the beginning of the period	48,881	46,851
Service cost	645	603	621
Interest cost	2,504	2,503	2,520
Benefits paid, inclusive of plan expenses	(1,709)	(1,481)
Plan settlements	(40)
Plan amendments		817
Plan combinations (including newly material plans)		337
Experience (gain) loss	5,442	(3,366)
Foreign currency translation adjustment	(1,828)	2,617
Benefit obligation at the end of the period	$ 53,895	$ 48,881	$ 46,851

Retirement Plans (Summary Of Change In Plan Assets) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
United States Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at the beginning of the period	$ 8,746	$ 7,859
Actual return on plan assets	420	1,102
Employer contributions	641	366
Benefits paid, inclusive of plan expenses	(615)	(581)
Fair value of plan assets at the end of the period	9,192	8,746
Funded status deficit	(4,848)	(3,157)
International Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at the beginning of the period	25,779	22,712
Actual return on plan assets	1,555	1,751
Employer contributions	1,505	1,424
Benefits paid, inclusive of plan expenses	(1,709)	(1,481)
Plan settlements	(40)
Foreign currency translation adjustments	(148)	1,373
Fair value of plan assets at the end of the period	26,942	25,779
Funded status deficit	$ (26,953)	$ (23,102)

Retirement Plans (Summary Of Amounts Recognized In The Balance Sheet) (Details) - USD ($) $ in Thousands	Mar. 31, 2012	Mar. 31, 2011
Retirement Plans [Abstract]
Other assets	$ 260	$ 2,513
Accrued expenses	(1,309)	(1,369)
Other liabilities	(30,752)	(27,403)
Amounts recognized in the consolidated balance sheets	$ (31,801)	$ (26,259)

This represents the noncurrent liability for underfunded plans recognized in the balance sheet that is associated with the defined benefit pension plans and other postretirement defined benefit plans.

Retirement Plans (Summary Of Amounts Recorded In AOCI Before Taxes) (Details) - USD ($) $ in Thousands	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
Retirement Plans [Abstract]
Prior service credit (cost)	$ (922)	$ (1,054)	$ (132)
Net gain (loss)	(11,176)	(3,712)	(7,344)
Net amount recognized	$ (12,098)	$ (4,766)	$ (7,476)

Amount related to the pretax cost of benefit changes attributable to plan participants' prior service pursuant to a plan amendment or a plan initiation, which has not yet been recognized as components of net periodic benefit cost.

Retirement Plans (Summary Of Changes In AOCI) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
Retirement Plans [Abstract]
New prior service cost		$ 905
Net loss/(gain) arising during the year	$ 7,757	(3,505)	$ 753
Effect of exchange rates on amounts included in AOCI	(176)	151	40
Amortization or curtailment recognition of prior service credit /(cost)	(83)	(62)	(142)
Amortization or settlement recognition of net gain/(loss)	(187)	(250)	(333)
Total recognized in other comprehensive income	$ 7,311	$ (2,761)	$ 318

The adjustment out of other comprehensive income for prior service costs recognized as a component of net period benefit cost during the period, after tax.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 158
-Paragraph 7
-Subparagraph a
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 158
-Paragraph 4
-Subparagraph c, d
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 130
-Paragraph 17, 19, 24
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 106
-Paragraph 52
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=6920043&loc=d3e637-108580

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=6920043&loc=d3e653-108580

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=6962843&loc=d3e1928-114920

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph 38
-Subparagraph c(3)
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

The cost (credit) resulting from a plan amendment that occurred during the period, after tax. The cost has not been recognized in net periodic benefit cost. A plan amendment includes provisions that grant increased benefits based on service rendered in prior periods.

The increase (decrease) to accumulated comprehensive income during the period related to benefit plans, after tax, attributable to the parent entity.

The accumulated change in the value of either the projected benefit obligation or the plan assets resulting from experience different from that assumed or from a change in an actuarial assumption that has not been recognized in net periodic benefit cost, after tax.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 158
-Paragraph 7
-Subparagraph a
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 158
-Paragraph 4
-Subparagraph c, d
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 130
-Paragraph 17, 19, 24
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=6920043&loc=d3e637-108580

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=6920043&loc=d3e653-108580

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6962843&loc=d3e1928-114920

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 55
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6920433&loc=d3e998-108581

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph 38
-Subparagraph c(3)
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

The adjustment out of other comprehensive income for actuarial gains or losses recognized as a component of net periodic benefit cost during the period, after tax.

Retirement Plans (Summary Of Recognized Components Of Net Periodic Pension Cost Included In Accumulated Other Comprehensive Income) (Details) $ in Thousands	12 Months Ended
	Mar. 31, 2012 USD ($)
Retirement Plans [Abstract]
Net loss	$ (81)
Net prior service cost	(534)
Net amount expected to be recognized	$ (615)

Retirement Plans (Summary Of Accumulated Benefit Obligation Related To All Defined Pension Plans) (Details) - USD ($) $ in Thousands	Mar. 31, 2012	Mar. 31, 2011
United States Plans [Member] \| All Defined Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	$ 14,040	$ 11,903
United States Plans [Member] \| Defined Benefit Plans With An Accumulated Benefit Obligation In Excess Of The Fair Value Of Plan Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	14,040	11,903
Accumulated benefit obligation	14,040	11,903
Fair value of plan assets	9,192	8,746
International Plans [Member] \| All Defined Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	50,416	46,225
International Plans [Member] \| Unfunded Defined Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	25,508	24,413
Projected benefit obligation	26,892	25,533
International Plans [Member] \| Defined Benefit Plans With An Accumulated Benefit Obligation In Excess Of The Fair Value Of Plan Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	28,003	25,560
Accumulated benefit obligation	26,445	$ 24,440
Fair value of plan assets	$ 789

Retirement Plans (Significant Assumptions Used To Determine The Net Periodic Benefit Cost) (Details)	12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
United States Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	5.70%	6.00%	6.50%
Expected return on plan assets	8.00%	8.00%	8.00%
Rate of compensation increase
Minimum [Member] \| International Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.00%	4.30%	3.80%
Expected return on plan assets	5.50%	5.50%	5.50%
Rate of compensation increase	2.00%	2.00%	2.00%
Maximum [Member] \| International Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	5.50%	6.00%	6.00%
Expected return on plan assets	7.00%	7.00%	7.00%
Rate of compensation increase	4.00%	3.50%	3.50%

Retirement Plans (Significant Assumptions Used To Determine The Projected Benefit Obligations) (Details)	Mar. 31, 2012	Mar. 31, 2011
United States Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.80%	5.70%
Expected return on plan assets	8.00%	8.00%
Rate of compensation increase
Minimum [Member] \| International Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	2.50%	4.00%
Expected return on plan assets	5.50%	5.50%
Rate of compensation increase	2.00%	2.00%
Maximum [Member] \| International Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	5.50%	5.50%
Expected return on plan assets	7.00%	7.00%
Rate of compensation increase	4.00%	4.00%

Retirement Plans (Summary Of Estimated Future Benefit Payments) (Details) $ in Thousands	Mar. 31, 2012 USD ($)
Retirement Plans [Abstract]
2013	$ 2,173
2014	2,319
2015	2,445
2016	2,674
2017	2,993
Years 2018-2022	$ 17,281

Stockholders' Equity (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Preferred stock, shares authorized	1,000,000	1,000,000
Preferred stock, par value	$ 0.01	$ 0.01
Number of shares of common stock purchased	2,646,885
Repurchased common stock value	$ 58,383
Treasury stock, Value	$ 78,183	$ 19,800
Maximum [Member]
Preferred stock, shares authorized	1,000,000

Equity impact of the cost of common and preferred stock that were repurchased during the period. Recorded using the cost method.

Stockholders' Equity (Change In Number Of Shares Of Common Stock Outstanding) (Details)	12 Months Ended
	Mar. 31, 2012 shares
Stockholders' Equity [Abstract]
Shares outstanding as of March 31, 2011	50,034,353
Repurchase of common shares	(2,646,885)
Shares issued as part of equity-based compensation plans, net of equity awards surrendered for option price and taxes	412,661
Shares outstanding as of March 31, 2012	47,800,129

Number of shares (or other type of equity) issued during the period as a result of any equity-based compensation plan other than an employee stock ownership plan (ESOP), net of any shares forfeited. Shares issued could result from the issuance of restricted stock, the exercise of stock options, stock issued under employee stock purchase plans, and/or other employee benefit plans.

Stockholders' Equity (Components Of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
Stockholders' Equity [Abstract]
Pension funded status adjustment, Beginning Balance	$ (3,512)	$ (5,479)	$ (4,794)
Unrealized gain (loss) on derivative instruments, Beginning Balance	4,436	(5,034)	(7,660)
Foreign currency translation adjustment, Beginning Balance	114,256	77,717	46,509
Accumulated other comprehensive income, Beginning Balance	115,180	67,204	34,055
Pension funded status adjustment, Before-Tax Amount	(7,311)	2,761	(318)
Unrealized gain (loss) on derivative instruments, Before-Tax Amount	(5,170)	14,721	4,047
Foreign currency translation adjustment, Before-Tax Amount	(32,356)	36,539	31,208
Accumulated other comprehensive income, Before-Tax Amount	(44,837)	54,021	34,937
Pension funded status adjustment, Tax Benefit (Expense)	1,841	(794)	(367)
Unrealized gain (loss) on derivative instruments, Tax Benefit (Expense)	1,909	(5,251)	(1,421)
Accumulated other comprehensive income, Tax Benefit (Expense)	3,750	(6,045)	(1,788)
Pension funded status adjustment, Net-of-Tax Amount	(5,470)	1,967	(685)
Unrealized gain (loss) on derivative instruments, Net-of-Tax Amount	(3,261)	9,470	2,626
Foreign currency translation adjustment, Net-of-Tax Amount	(32,356)	36,539	31,208
Accumulated other comprehensive income, Net-of-Tax Amount	(41,087)	47,976	33,149
Pension funded status adjustment, Ending Balance	(8,982)	(3,512)	(5,479)
Unrealized gain (loss) on derivative instruments, Ending Balance	1,175	4,436	(5,034)
Foreign currency translation adjustment, Ending Balance	81,900	114,256	77,717
Accumulated other comprehensive income, Ending Balance	$ 74,093	$ 115,180	$ 67,204

Secondary Offerings Of Common Shares (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2011	Mar. 31, 2010
Secondary Offerings Of Common Shares [Abstract]
Stockholders sold, common stock pursuant to effective shelf registration filed	2,845,869	3,200,000
Fees incurred related to the offerings	$ 615	$ 150

Stock-Based Compensation (Narrative) (Details) $ in Thousands		12 Months Ended
	May 14, 2012 shares	Mar. 31, 2012 USD ($) mo yr $ / shares shares	Mar. 31, 2011 USD ($) yr $ / shares shares	Mar. 31, 2010 USD ($) yr $ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future grants		2,872,490
Stock-based compensation expense \| $		$ 1,092	$ 2,333	$ 2,993
Stock-based compensation expense, net of tax \| $		822	$ 1,844	2,095
Unrecognized compensation expense associated with non-vested incentive awards outstanding \| $		$ 18,451
Expected weighted average period \| mo		19
Stock Options Issued Prior To Fiscal 2009 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		3 years
Stock Options Issued Prior To Fiscal 2008 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		4 years
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years
Stock unit grant during period	223,224
Market Share Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate \| $ / shares		0.93%	1.30%
Dividend yield		0.00%	0.00%
Time of maturity, in years \| yr		3	3
Expected volatility		45.50%	43.00%
Restricted Stock Units And Market Share Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense \| $		$ 10,493	$ 6,723	3,968
Share-based compensation, tax benefit \| $		$ 2,599	$ 1,659	$ 1,190
Market share units converted in to shares of common stock		zero and two shares
Conversion ratio		2
10 Year Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate				2.01%
Dividend yield				0.00%
Time of maturity, in years \| yr				5
Expected volatility				56.60%
Weighted average fair value \| $ / shares				$ 8.35
3.5 Year Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate				0.93%
Dividend yield				0.00%
Time of maturity, in years \| yr				2
Expected volatility				56.60%
Weighted average fair value \| $ / shares				$ 5.15
Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock shares reserves for grant		3,177,477
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Market share units converted into common stock for each unit		2
Maximum [Member] \| Stock Options Issued In Fiscal 2010 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		3 years
Options expiration period (in years) \| yr		10
Maximum [Member] \| Restricted Stock Units And Market Share Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Market share units converted into common stock for each unit		2.0
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Market share units converted into common stock for each unit		0
Minimum [Member] \| Stock Options Issued In Fiscal 2010 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		6 months
Options expiration period (in years) \| yr		3.5
Minimum [Member] \| Restricted Stock Units And Market Share Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Market share units converted into common stock for each unit		0
Management And Other Key Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		4 years	4 years
Percentage of restricted stock units granted, vested per year		25.00%	25.00%
Management And Other Key Employees [Member] \| Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Market price per unit of stock award \| $ / shares		$ 35.79	$ 25.67
Stock unit grant during period		95,026	291,701
Management And Other Key Employees [Member] \| Market Share Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Market price per unit of stock award \| $ / shares		$ 48.36	$ 34.45
Stock unit grant during period		224,397	124,091
Non-Employee Directors [Member] \| Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			13 months
Restricted stock units granted		35,632	21,248
Market price per unit of stock award \| $ / shares		$ 22.45	$ 22.59
Deferred Compensation Plans [Member] \| Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units granted		9,340

Stock-Based Compensation (Summary Of Weighted Average Fair Value Of Options Granted) (Details)	12 Months Ended
	Mar. 31, 2010 yr $ / shares	Mar. 31, 2012 $ / shares	Mar. 31, 2011 $ / shares	Mar. 31, 2009 $ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price	$ 17.69	$ 20.85	$ 19.52	$ 16.70
10 Year Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price	$ 16.20
Risk-free interest rate	2.01%
Dividend yield	0.00%
Expected life, years \| yr	5
Expected volatility	56.60%
Weighted average fair value	$ 8.35
3.5 Year Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price	$ 16.24
Risk-free interest rate	0.93%
Dividend yield	0.00%
Expected life, years \| yr	2
Expected volatility	56.60%
Weighted average fair value	$ 5.15

Stock-Based Compensation (Summary Of Stock Option Activity) (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Mar. 31, 2012 USD ($) yr $ / shares shares	Mar. 31, 2011 USD ($) yr $ / shares shares	Mar. 31, 2010 USD ($) yr $ / shares shares
Stock-Based Compensation [Abstract]
Number of Options outstanding, Beginning Balance \| shares	860,779	2,431,233	2,643,175
Number of Options, Granted \| shares			539,506
Number of Options, Exercised \| shares	(227,116)	(1,415,391)	(667,862)
Number of Options, Canceled \| shares		(155,063)	(83,586)
Number of Options outstanding, Ending Balance \| shares	633,663	860,779	2,431,233
Options outstanding, Weighted Average Remaining Contract Term, Beginning Balance \| yr	6.2	4.0	4.2
Options outstanding, Weighted Average Exercise Price, Beginning Balance \| $ / shares	$ 19.52	$ 17.69	$ 16.70
Weighted Average Exercise Price, Granted \| $ / shares			16.21
Weighted Average Exercise Price, Exercised \| $ / shares	15.82	15.34	12.22
Weighted Average Exercise Price, Canceled \| $ / shares		29.32	21.43
Options outstanding, Weighted Average Exercise Price, Ending Balance \| $ / shares	$ 20.85	$ 19.52	$ 17.69
Options outstanding, Weighted Average Remaining Contract Term, Ending Balance \| yr	6.1	6.2	4.0
Options outstanding, Aggregate Intrinsic Value, Beginning Balance \| $	$ 17,129	$ 19,191	$ 1,752
Aggregate Intrinsic Value, Exercised \| $	3,691	18,482	7,125
Aggregate Intrinsic Value, Canceled \| $		9	522
Options outstanding, Aggregate Intrinsic Value, Ending Balance \| $	$ 8,879	$ 17,129	$ 19,191
Options exercisable, Number of Options, Ending Balance \| shares	523,626
ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm \| yr	5.9
Options exercisable, Weighted Average Exercise Price, Ending Balance \| $ / shares	$ 21.82
Options exercisable, Aggregate Intrinsic Value, Ending Balance \| $	$ 6,826
Options expected to vest, Number of Options, Ending Balance \| shares	110,037
ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm \| yr	7.1
Options expected to vest, Weighted Average Exercise Price, Ending Balance \| $ / shares	$ 16.20
Options expected to vest, Aggregate Intrinsic Value, Ending Balance \| $	$ 2,053

Stock-Based Compensation (Summary Of Information Regarding Stock Options Outstanding And Exercisable) (Details)	Mar. 31, 2012 yr $ / shares shares
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Number of Options \| shares	633,663
Options Outstanding, Weighted Average Remaining Contractual Life \| yr	6.1
Options Outstanding, Weighted Average Exercise Price \| $ / shares	$ 20.85
Options Exercisable, Number of Options \| shares	523,626
Options Exercisable, Weighted Average Exercise Price \| $ / shares	$ 21.82
$10.01-15.00 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Number of Options \| shares	65,954
Options Outstanding, Weighted Average Remaining Contractual Life \| yr	3.1
Options Outstanding, Weighted Average Exercise Price \| $ / shares	$ 14.12
Options Exercisable, Number of Options \| shares	65,954
Options Exercisable, Weighted Average Exercise Price \| $ / shares	$ 14.12
$15.01-20.00 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Number of Options \| shares	361,661
Options Outstanding, Weighted Average Remaining Contractual Life \| yr	6.6
Options Outstanding, Weighted Average Exercise Price \| $ / shares	$ 16.75
Options Exercisable, Number of Options \| shares	251,624
Options Exercisable, Weighted Average Exercise Price \| $ / shares	$ 16.99
Over $20.00 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Number of Options \| shares	206,048
Options Outstanding, Weighted Average Remaining Contractual Life \| yr	6.1
Options Outstanding, Weighted Average Exercise Price \| $ / shares	$ 30.19
Options Exercisable, Number of Options \| shares	206,048
Options Exercisable, Weighted Average Exercise Price \| $ / shares	$ 30.19

Stock-Based Compensation (Summary Of Changes Of Non-Vested Options) (Details)	12 Months Ended
	Mar. 31, 2012 $ / shares shares
Stock-Based Compensation [Abstract]
Nonvested, Number of Options, Beginning Balance \| shares	357,903
Number of Options, Vested \| shares	(247,866)
Nonvested, Number of Options, Ending Balance \| shares	110,037
Weighted Average Grant-Date Fair Value, Nonvested, Beginning Balance \| $ / shares	$ 8.70
Weighted Average Grant-Date Fair Value, Vested \| $ / shares	9.06
Weighted Average Grant-Date Fair Value, Nonvested, Ending Balance \| $ / shares	$ 7.87

Stock-Based Compensation (Summary Of The Changes In Restricted Stock Units And Market Share Units) (Details) - Restricted Stock Units (RSU) / Market Share Units (MSU) [Member]	12 Months Ended
	Mar. 31, 2012 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of RSU and MSU, Non-vested awards, Beginning Balance \| shares	865,392
Number of RSU and MSU, Granted \| shares	364,395
Number of RSU and MSU, Vested \| shares	(259,151)
Number of RSU and MSU, Cancelled \| shares	(6,833)
Number of RSU and MSU, Non-vested awards, Ending Balance \| shares	963,803
Weighted Average Grant Date Fair Value, Non-vested awards, Beginning Balance \| $ / shares	$ 23.97
Weighted Average Grant Date Fair Value, Granted \| $ / shares	40.76
Weighted Average Grant Date Fair Value, Vested \| $ / shares	22.28
Weighted Average Grant Date Fair Value, Canceled \| $ / shares	11.49
Weighted Average Grant Date Fair Value, Non-vested awards, Ending Balance \| $ / shares	$ 30.84

Earnings Per Share (Narrative) (Details) $ in Thousands	12 Months Ended
Earnings Per Share (Narrative) (Details) $ in Thousands	Mar. 31, 2012 USD ($) shares
Earnings Per Share [Abstract]
Convertible Notes \| $	$ 172,500
Aggregate consideration on conversion shares \| shares	4,248,761

Earnings Per Share (Reconciliation From Basic To Diluted Average Common Shares And Net Earnings Per Common Share) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2012	Jan. 01, 2012	Oct. 02, 2011	Jul. 03, 2011	Mar. 31, 2011	Jan. 02, 2011	Oct. 03, 2010	Jul. 04, 2010	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
Earnings Per Share [Abstract]
Net earnings attributable to EnerSys stockholders	$ 45,359	$ 36,859	$ 28,289	$ 33,496	$ 30,091	$ 33,759	$ 26,549	$ 23,027	$ 144,003	$ 113,426	$ 62,304
Basic (weighted-average outstanding shares)									48,748,205	49,376,132	48,122,207
Dilutive potential common shares from exercise and lapse of equity awards, net of shares assumed reacquired									467,830	668,114	711,888
Diluted (weighted-average outstanding shares)									49,216,035	50,044,246	48,834,095
Basic earnings per common share attributable to EnerSys stockholders	$ 0.95	$ 0.77	$ 0.57	$ 0.67	$ 0.60	$ 0.68	$ 0.54	$ 0.47	$ 2.95	$ 2.30	$ 1.29
Diluted earnings per common share attributable to EnerSys stockholders	$ 0.94	$ 0.77	$ 0.57	$ 0.66	$ 0.59	$ 0.67	$ 0.53	$ 0.47	$ 2.93	$ 2.27	$ 1.28
Anti-dilutive equity awards not included in weighted average common shares-diluted									221,097		383,696

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 128
-Paragraph 13, 14
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 128
-Paragraph 171
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 128
-Paragraph 40
-Subparagraph c
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Diluted Earnings Per Share
-URI http://asc.fasb.org/extlink&oid=6510752

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Contingent Stock Agreement
-URI http://asc.fasb.org/extlink&oid=6508534

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Antidilution
-URI http://asc.fasb.org/extlink&oid=6505113

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Emerging Issues Task Force (EITF)
-Number 07-4
-Paragraph 4
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 128
-Paragraph 36, 37, 38
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 5
-Section 03
-Paragraph 20

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Article 7
-Paragraph 18

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Paragraph 21
-Article 9

Reference 5: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.21)
-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
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-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6920599&loc=d3e1252-109256

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
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-Paragraph 52
-URI http://asc.fasb.org/extlink&oid=6945512&loc=d3e4984-109258

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
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-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.23)
-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04.19)
-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Emerging Issues Task Force (EITF)
-Number 07-4
-Paragraph 4
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Emerging Issues Task Force (EITF)
-Number 87-21
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph 38
-Subparagraph a
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 130
-Paragraph 10, 15
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 95
-Paragraph 28, 29, 30
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 5
-Section 03
-Paragraph 19

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Paragraph 20
-Article 9

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3602-108585

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Net Income
-URI http://asc.fasb.org/extlink&oid=6518256

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Other Comprehensive Income
-URI http://asc.fasb.org/extlink&oid=6519514

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.18)
-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04.19)
-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6920043&loc=d3e565-108580

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
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-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04.22)
-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

Reference 15: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph 38
-Subparagraph d
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 16: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph A7
-Appendix A

The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 128
-Paragraph 171
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 128
-Paragraph 40
-Subparagraph a
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 128
-Paragraph 8
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=6920599&loc=d3e1448-109256

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Weighted-Average Number of Common Shares Outstanding
-URI http://asc.fasb.org/extlink&oid=6528421

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Emerging Issues Task Force (EITF)
-Number 07-4
-Paragraph 4
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Commitments, Contingencies And Litigation (Details) € in Thousands, $ in Thousands, lb in Millions	3 Months Ended		12 Months Ended
	Oct. 02, 2011 EUR (€)	Oct. 02, 2011 USD ($)	Mar. 31, 2012 USD ($) lb	Mar. 31, 2011 USD ($) lb	Mar. 31, 2009 EUR (€)	Mar. 31, 2009 USD ($)
Commitments, Contingencies And Litigation [Line Items]
Litigation damages assessed and paid					€ 2,700	$ 4,200
Refund from damages paid	€ 671	$ 900
Average term of collective bargaining agreements			2 years
Longest term of collective bargaining agreements			4 years
Percentage of employees covered by collective bargaining agreements			40.00%
Company number of employees			9,200
Reserves of environmental liabilities			$ 2,995	$ 3,279
Lead Hedge Forward Contracts [Member]
Commitments, Contingencies And Litigation [Line Items]
Purchase price of hedges, pounds of lead \| lb			60.0	63.4
Purchase price of hedges			$ 56,610	$ 68,212
Foreign Currency Forward Contracts [Member]
Commitments, Contingencies And Litigation [Line Items]
Purchase price of hedges			53,531	82,829
Interest Rate Swap Agreements [Member]
Commitments, Contingencies And Litigation [Line Items]
Convertible interest rate swap			$ 85,000	$ 85,000
Maximum [Member]
Commitments, Contingencies And Litigation [Line Items]
Expiration year of collective bargaining agreements			2014
Minimum [Member]
Commitments, Contingencies And Litigation [Line Items]
Expiration year of collective bargaining agreements			2012

Restructuring Plans (Narrative) (Details) $ in Thousands	3 Months Ended	12 Months Ended		36 Months Ended
Restructuring Plans (Narrative) (Details) $ in Thousands	Jan. 02, 2011 employee	Mar. 31, 2012 USD ($) employee	Mar. 31, 2011 USD ($) employee	Mar. 31, 2012 USD ($)	Mar. 31, 2011 USD ($)
Restructuring Cost and Reserve [Line Items]
Reduction in number of employees \| employee		470
Costs incurred by the Company against the accrual		$ 2,270
Restructuring charges incurred to date					$ 31,894
Oerlikon [Member]
Restructuring Cost and Reserve [Line Items]
Number of manufacturing facilities closed	2
Reduction in number of employees \| employee	100
Restructuring charges incurred to date				$ 4,526
European And American Operations [Member]
Restructuring Cost and Reserve [Line Items]
Expected additional restructuring charges		105
Accrual adjustment		246
Workforce Reduction [Member] \| Europe [Member]
Restructuring Cost and Reserve [Line Items]
Costs incurred by the Company against the accrual		3,263	$ 1,316
Accrual adjustment		435
Restructuring charges incurred to date		1,783	$ 3,830
Workforce Reduction [Member] \| European Operations [Member]
Restructuring Cost and Reserve [Line Items]
Reduction in number of employees \| employee			60
Restructuring reserve		$ 556		556
Severance-related costs			$ 5,200
Relocation Of Manufacturing [Member] \| European Operations [Member]
Restructuring Cost and Reserve [Line Items]
Reduction in number of employees		80
Restructuring reserve		$ 630		$ 630
Costs incurred by the Company against the accrual		2,433
Expected additional restructuring charges		1,100
Severance-related costs		4,200
Restructuring charges incurred to date		$ 3,070

Restructuring Plans (Acquisition And Non-Acquisition Related Restructuring Reserve) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
Acquisition Related Restructuring Reserve [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	$ 403	$ 1,292
Accrued	711	2,546	$ 1,269
Costs incurred	(1,114)	(3,420)
Foreign currency impact and other		(15)	23
Ending Balance		403	1,292
Non-Acquisition Related Restructuring Plans [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	4,920	7,482	10,289
Accrual adjustment	(681)
Accrued	4,958	4,267	12,370
Costs incurred	(7,966)	(6,945)	(15,539)
Foreign currency impact and other	(45)	116	362
Ending Balance	1,186	4,920	7,482
Employee Severance [Member] \| Acquisition Related Restructuring Reserve [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	257	1,292
Accrued	81	108	1,269
Costs incurred	(338)	(1,107)
Foreign currency impact and other		(36)	23
Ending Balance		257	1,292
Employee Severance [Member] \| Non-Acquisition Related Restructuring Plans [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	4,920	7,482	10,289
Accrual adjustment	(681)
Accrued	4,958	4,267	10,107
Costs incurred	(7,966)	(6,945)	(13,276)
Foreign currency impact and other	(45)	116	362
Ending Balance	1,186	4,920	7,482
Plant Closure And Other [Member] \| Acquisition Related Restructuring Reserve [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	146
Accrued	630	2,438
Costs incurred	$ (776)	(2,313)
Foreign currency impact and other		21
Ending Balance		$ 146
Plant Closure And Other [Member] \| Non-Acquisition Related Restructuring Plans [Member]
Restructuring Cost and Reserve [Line Items]
Accrued			2,263
Costs incurred			$ (2,263)

Warranty (Analysis Of Changes In Liability For Product Warranties) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
Warranty [Abstract]
Balance at beginning of period	$ 36,006	$ 31,739	$ 30,914
Current year provisions	26,841	20,565	13,123
Costs incurred	(20,185)	(17,499)	(13,283)
Foreign exchange and other	(595)	1,201	985
Balance at end of period	$ 42,067	$ 36,006	$ 31,739

Other (Income) Expense, Net And Charges Related To Refinancing (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2011	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
Other (Income) Expense, Net And Charges Related To Refinancing [Abstract]
Charges related to refinancing	$ 8,155		$ 8,155
Write offs of deferred financing fees			2,308
Interest rate swap agreements, losses from discontinued hedging accounting			$ 5,847

Other (Income) Expense, Net And Charges Related To Refinancing (Summary Of Other (Income) Expense, Net) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
Other (Income) Expense, Net And Charges Related To Refinancing [Abstract]
Foreign exchange transaction losses	$ 1,483	$ 732	$ 3,045
Secondary offering fees		615	150
Other	1,585	830	1,189
Total	$ 3,068	$ 2,177	$ 4,384

Other (Income) Expense, Net And Charges Related To Refinancing (Summary Of Charges Related To Refinancing) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2011	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
Other (Income) Expense, Net And Charges Related To Refinancing [Abstract]
Charges related to refinancing	$ 8,155		$ 8,155

Operations By Industry Segment And Geographic Area (Narrative) (Details)	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
Segment Reporting Information [Line Items]
Operations in number of countries	100
United States [Member]
Segment Reporting Information [Line Items]
Percentage of sales to customers	42.60%	41.30%	40.40%

Operations By Industry Segment And Geographic Area (Summary Of Financial Information Related To The Company's Business Segments) (Details) - USD ($)
$ in Thousands

3 Months Ended

12 Months Ended

Mar. 31, 2012

Jan. 01, 2012

Oct. 02, 2011

Jul. 03, 2011

Mar. 31, 2011

Jan. 02, 2011

Oct. 03, 2010

Jul. 04, 2010

Mar. 31, 2012

Mar. 31, 2011

Mar. 31, 2010

$ 592,754

$ 574,246

$ 547,140

$ 569,229

$ 548,054

$ 508,596

$ 472,843

$ 434,969

$ 2,283,369

$ 1,964,462

$ 1,579,385

^[1]

134,949

119,076

75,534

900

(2,236)

(1,440)

(902)

(410)

(1,586)

(1,754)

(2,750)

(723)

(4,988)

(6,813)

(13,929)

2,919

65,879

^[2]

$ 53,777

^[2]

$ 42,440

^[2]

$ 48,715

^[2]

53,518

^[3]

$ 48,320

^[3]

$ 44,496

^[3]

$ 37,480

^[3]

210,811

^[2],[4]

183,814

^[3],[4]

114,297

^[4]

353,215

344,385

353,215

344,385

315,141

48,943

59,940

45,111

50,360

44,393

44,851

Europe [Member]

995,431

890,313

741,975

75,652

55,586

37,449

900

(4,988)

(6,813)

(13,212)

2,919

63,872

55,643

17,649

161,854

169,056

161,854

169,056

156,953

21,631

22,034

20,624

25,451

21,564

22,348

Americas [Member]

1,082,747

896,629

700,297

38,115

42,141

24,848

(717)

138,894

124,515

87,156

144,701

142,263

144,701

142,263

138,217

20,862

22,368

21,089

21,466

19,842

19,189

Asia [Member]

205,191

177,520

137,113

21,182

21,349

13,237

12,133

10,469

20,502

$ 46,660

$ 33,066

46,660

33,066

19,971

6,450

15,538

3,398

3,443

2,987

3,314

Reserve Power [Member]

1,092,734

970,480

820,526

Motive Power [Member]

$ 1,190,635

$ 993,982

$ 758,859

[1]	Intersegment sales are presented on a cost plus basis which takes into consideration the effect of transfer prices between legal entities.
[2]	Included in Operating earnings were restructuring charges of $410, $902, $1,440 and $2,236 for the first, second, third and fourth quarters of fiscal 2012, respectively. Operating earnings also included a legal proceedings settlement income of $900, in the second quarter of fiscal 2012.
[3]	Included in Operating earnings were restructuring charges of $723, $2,750, $1,754 and $1,586 for the first, second, third and fourth quarters of fiscal 2011, respectively.
[4]	The Company does not allocate interest expense or other (income) expense to the reportable segments.

Quarterly Financial Data (Summary Of Interim Financial Information) (Details) - USD ($)
$ / shares in Units, $ in Thousands

3 Months Ended

12 Months Ended

Mar. 31, 2012

Jan. 01, 2012

Oct. 02, 2011

Jul. 03, 2011

Mar. 31, 2011

Jan. 02, 2011

Oct. 03, 2010

Jul. 04, 2010

Mar. 31, 2012

Mar. 31, 2011

Mar. 31, 2010

Quarterly Financial Data [Abstract]

Net sales

$ 592,754

$ 574,246

$ 547,140

$ 569,229

$ 548,054

$ 508,596

$ 472,843

$ 434,969

$ 2,283,369

$ 1,964,462

$ 1,579,385

Gross profit

145,463

^[1]

130,876

^[1]

114,395

^[1]

121,971

^[1]

124,609

117,900

110,721

96,614

512,705

^[1]

449,844

360,904

Operating earnings

65,879

^[2]

53,777

^[2]

42,440

^[2]

48,715

^[2]

53,518

^[1]

48,320

^[1]

44,496

^[1]

37,480

^[1]

210,811

^[2],[3]

183,814

^[1],[3]

114,297

^[3]

Net earnings attributable to EnerSys stockholders

45,323

36,859

28,289

33,496

30,091

^[4]

33,759

^[4]

26,549

^[4]

23,027

^[4]

143,967

113,426

^[4]

62,304

$ 45,359

$ 36,859

$ 28,289

$ 33,496

$ 30,091

$ 33,759

$ 26,549

$ 23,027

$ 144,003

$ 113,426

$ 62,304

Net earnings per common share attributable to EnerSys stockholders-basic

$ 0.95

$ 0.77

$ 0.57

$ 0.67

$ 0.60

$ 0.68

$ 0.54

$ 0.47

$ 2.95

$ 2.30

$ 1.29

Net earnings per common share attributable to EnerSys stockholders-diluted

$ 0.94

$ 0.77

$ 0.57

$ 0.66

$ 0.59

$ 0.67

$ 0.53

$ 0.47

$ 2.93

$ 2.27

$ 1.28

$ 2,236

$ 1,440

$ 902

$ 410

$ 1,586

$ 1,754

$ 2,750

$ 723

$ 4,988

$ 6,813

$ 13,929