Commitments, Contingencies and Litigation	12 Months Ended
Mar. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments, Contingencies and Litigation	Commitments, Contingencies and Litigation Litigation and Other Legal Matters In the ordinary course of business, the Company and its subsidiaries are routinely defendants in or parties to many pending and threatened legal actions and proceedings, including actions brought on behalf of various classes of claimants. These actions and proceedings are generally based on alleged violations of environmental, anticompetition, employment, contract and other laws. In some of these actions and proceedings, claims for substantial monetary damages are asserted against the Company and its subsidiaries. In the ordinary course of business, the Company and its subsidiaries are also subject to regulatory and governmental examinations, information gathering requests, inquiries, investigations, and threatened legal actions and proceedings. In connection with formal and informal inquiries by federal, state, local and foreign agencies, such subsidiaries receive numerous requests, subpoenas and orders for documents, testimony and information in connection with various aspects of their activities. European Competition Investigations Certain of the Company’s European subsidiaries have received subpoenas and requests for documents and, in some cases, interviews from, and have had on-site inspections conducted by the competition authorities of Belgium, Germany and the Netherlands relating to conduct and anticompetitive practices of certain industrial battery participants. The Company is responding to inquiries related to these matters. The Company settled the Belgian regulatory proceeding in February 2016 by acknowledging certain anticompetitive practices and conduct and agreeing to pay a fine of $1,962, which was paid in March 2016. As of March 31, 2017 and March 31, 2016, the Company had a reserve balance of $1,830 and $2,038, respectively, relating to the Belgian regulatory proceeding. The change in the reserve balance between March 31, 2017 and March 31, 2016 was solely due to foreign currency translation impact. As of January 1, 2017, the Company had estimated an aggregate range of possible loss associated with the German regulatory proceeding of $17,000 to $26,000 and reserved $17,000 with respect to the German regulatory proceeding. Based on the continued evolution of facts and its interactions with the German competition authority in regard to this matter, the Company has further refined its estimate for a portion of this proceeding to be $13,463 as of March 31, 2017. The Company does not believe that an estimate can be made at this time given the current stage of the remaining portion of this proceeding. For the Dutch regulatory proceeding, the Company reserved $10,258 as of March 31, 2017. As of March 31, 2017 and March 31, 2016, the Company had a total reserve balance of $25,551 and $2,038, respectively, in connection with these remaining investigations and other related legal matters, included in accrued expenses on the Consolidated Balance Sheets. The foregoing estimate of losses is based upon currently available information for these proceedings. However, the precise scope, timing and time period at issue, as well as the final outcome of the investigations or customer claims, remain uncertain. Accordingly, the Company’s estimate may change from time to time, and actual losses could vary. Altergy In the fourth quarter of fiscal 2014, the Company recorded a $58,184 legal proceedings charge in connection with an adverse arbitration result involving disputes between the Company's wholly-owned subsidiary, EnerSys Delaware Inc. (“EDI”), and Altergy Systems (“Altergy”). In accordance with the final term sheet, EDI paid Altergy $40,000 in settlement of this award. Altergy paid $2,000 to purchase EDI’s entire equity interest in Altergy. Since the full amount of the initial award of $58,184 was recorded in fiscal 2014, the Company reversed approximately $16,233, net of professional fees, from this previously recorded legal proceedings charge in fiscal 2015 and $799 in fiscal 2016. The Company also included the $2,000 received in exchange for its equity interest in Altergy in the Consolidated Statements of Income in Other (income) expense, net in fiscal 2015. The Company had previously written off the carrying value of the investment of $5,000 in fiscal 2014. 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 the Company established a reserve for this facility which was $1,123 as of March 31, 2017 and 2016. Based on current information, the Company’s management believes this reserve is adequate to satisfy the Company’s environmental liabilities at this facility. This facility is separate from the Company’s current metal fabrication facility in Sumter. Collective Bargaining At March 31, 2017, the Company had approximately 9,400 employees. Of these employees, approximately 29% were covered by collective bargaining agreements. Employees covered by collective bargaining agreements that did not exceed twelve months were approximately 7% of the total workforce. The average term of these agreements is 2 years, with the longest term being 3 years. The Company considers its employee relations to be good and did not experience any significant labor unrest or disruption of production during fiscal 2017. 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, 2017 and 2016, the Company has hedged the price to purchase approximately 45.0 million pounds and 27.4 million pounds of lead, respectively, for a total purchase price of $46,550 and $21,628, 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 vast majority of such contracts are for a period not extending beyond one year. The Company’s largest exposure is from the purchase and conversion of U.S. dollar based lead costs into local currencies in EMEA. Additionally, the Company has currency exposures from intercompany financing and intercompany and third-party trade transactions. To hedge these exposures, the Company has entered into a total of $44,311 and $29,362, respectively, of foreign currency forward contracts and options with financial institutions as of March 31, 2017 and 2016, respectively. Other The Company has various purchase and capital commitments incident to the ordinary conduct of business. In the aggregate, such commitments are not at prices in excess of current market.

In the ordinary course of business, the Company and its subsidiaries are routinely defendants in or parties to many pending and threatened legal actions and proceedings, including actions brought on behalf of various classes of claimants. These actions and proceedings are generally based on alleged violations of environmental, anticompetition, employment, contract and other laws. In some of these actions and proceedings, claims for substantial monetary damages are asserted against the Company and its subsidiaries. In the ordinary course of business, the Company and its subsidiaries are also subject to regulatory and governmental examinations, information gathering requests, inquiries, investigations, and threatened legal actions and proceedings. In connection with formal and informal inquiries by federal, state, local and foreign agencies, such subsidiaries receive numerous requests, subpoenas and orders for documents, testimony and information in connection with various aspects of their activities.

Certain of the Company’s European subsidiaries have received subpoenas and requests for documents and, in some cases, interviews from, and have had on-site inspections conducted by the competition authorities of Belgium, Germany and the Netherlands relating to conduct and anticompetitive practices of certain industrial battery participants. The Company is responding to inquiries related to these matters. The Company settled the Belgian regulatory proceeding in February 2016 by acknowledging certain anticompetitive practices and conduct and agreeing to pay a fine of $1,962, which was paid in March 2016. As of March 31, 2017 and March 31, 2016, the Company had a reserve balance of $1,830 and $2,038, respectively, relating to the Belgian regulatory proceeding. The change in the reserve balance between March 31, 2017 and March 31, 2016 was solely due to foreign currency translation impact. As of January 1, 2017, the Company had estimated an aggregate range of possible loss associated with the German regulatory proceeding of $17,000 to $26,000 and reserved $17,000 with respect to the German regulatory proceeding. Based on the continued evolution of facts and its interactions with the German competition authority in regard to this matter, the Company has further refined its estimate for a portion of this proceeding to be $13,463 as of March 31, 2017. The Company does not believe that an estimate can be made at this time given the current stage of the remaining portion of this proceeding. For the Dutch regulatory proceeding, the Company reserved $10,258 as of March 31, 2017. As of March 31, 2017 and March 31, 2016, the Company had a total reserve balance of $25,551 and $2,038, respectively, in connection with these remaining investigations and other related legal matters, included in accrued expenses on the Consolidated Balance Sheets. The foregoing estimate of losses is based upon currently available information for these proceedings. However, the precise scope, timing and time period at issue, as well as the final outcome of the investigations or

In the fourth quarter of fiscal 2014, the Company recorded a $58,184 legal proceedings charge in connection with an adverse arbitration result involving disputes between the Company's wholly-owned subsidiary, EnerSys Delaware Inc. (“EDI”), and Altergy Systems (“Altergy”). In accordance with the final term sheet, EDI paid Altergy $40,000 in settlement of this award. Altergy paid $2,000 to purchase EDI’s entire equity interest in Altergy. Since the full amount of the initial award of $58,184 was recorded in fiscal 2014, the Company reversed approximately $16,233, net of professional fees, from this previously recorded legal proceedings charge in fiscal 2015 and $799 in fiscal 2016. The Company also included the $2,000 received in exchange for its equity interest in Altergy in the Consolidated Statements of Income in Other (income) expense, net in fiscal 2015. The Company had previously written off the carrying value of the investment of $5,000 in fiscal 2014.

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 the Company established a reserve for this facility which was $1,123 as of March 31, 2017 and 2016. Based on current information, the Company’s management believes this reserve is adequate to satisfy the Company’s environmental liabilities at this facility. This facility is separate from the Company’s current metal fabrication facility in Sumter.

At March 31, 2017, the Company had approximately 9,400 employees. Of these employees, approximately 29% were covered by collective bargaining agreements. Employees covered by collective bargaining agreements that did not exceed twelve months were approximately 7% of the total workforce. The average term of these agreements is 2 years, with the longest term being 3 years. The Company considers its employee relations to be good and did not experience any significant labor unrest or disruption of production during fiscal 2017.

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, 2017 and 2016, the Company has hedged the price to purchase approximately 45.0 million pounds and 27.4 million pounds of lead, respectively, for a total purchase price of $46,550 and $21,628, respectively.

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 vast majority of such contracts are for a period not extending beyond one year. The Company’s largest exposure is from the purchase and conversion of U.S. dollar based lead costs into local currencies in EMEA. Additionally, the Company has currency exposures from intercompany financing and intercompany and third-party trade transactions. To hedge these exposures, the Company has entered into a total of $44,311 and $29,362, respectively, of foreign currency forward contracts and options with financial institutions as of March 31, 2017 and 2016, respectively.