v3.7.0.1

Commitments, Contingencies and Litigation - Additional Information (Detail) $ in Thousands, lb in Millions | 1 Months Ended | 3 Months Ended | 6 Months Ended | 9 Months Ended | 12 Months Ended
--- | --- | --- | --- | --- | ---
Mar. 31, 2016 USD ($) | Mar. 31, 2017 USD ($) Employee | Jan. 01, 2017 USD ($) | Sep. 27, 2015 USD ($) | Sep. 28, 2014 USD ($) | Mar. 31, 2014 USD ($) | Dec. 29, 2013 USD ($) | Sep. 28, 2014 USD ($) | Jan. 01, 2017 USD ($) | Mar. 31, 2017 USD ($) Employee lb | Mar. 31, 2016 USD ($) lb | Mar. 31, 2015 USD ($) | Mar. 31, 2014 USD ($)
Commitments, Contingencies And Litigation [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Penalties paid relating to anti-competition investigations | $ 1,962 |  |  |  |  |  |  |  |  |  |  |  |
Reserves for anti-competition investigations |  | $ 25,551 |  |  |  |  |  |  |  | $ 25,551 |  |  |
Legal proceedings charge |  | $ 6,725 | $ 17,000 | $ 3,201 |  |  |  |  |  | 23,725 | $ 3,201 | $ (16,233) |
Payments for legal settlements |  |  |  |  |  |  |  | $ 40,000 |  |  |  |  |
Payments for (proceeds from) other investing activities |  |  |  |  |  |  |  |  |  | 0 | 0 | (2,000) | $ (2,000)
Gain (loss) related to litigation settlement |  |  |  |  |  |  |  |  |  | (23,725) | $ 799 | $ 16,233 |
Gain (loss) on sale of assets and asset impairment charges |  |  |  |  | $ 2,000 |  |  |  |  |  |  |  |
Other asset impairment charges |  |  |  |  |  |  | $ 5,000 |  |  |  |  |  |
Reserves of environmental liabilities |  |  |  |  |  |  |  |  |  | $ 1,123 |  |  |
Company number of employees | Employee |  | 9,400 |  |  |  |  |  |  |  | 9,400 |  |  |
Percentage of employees covered by collective bargaining agreements |  |  |  |  |  |  |  |  |  | 29.00% |  |  |
Percentage of collective bargaining agreements that expire in next twelve months |  |  |  |  |  |  |  |  |  | 7.00% |  |  |
Average term of collective bargaining agreements |  |  |  |  |  |  |  |  |  | 2 years |  |  |
Longest term of collective bargaining agreements |  |  |  |  |  |  |  |  |  | 3 years |  |  |
Lead hedge forward contracts |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments, Contingencies And Litigation [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Purchase price of hedges, pounds of lead | lb |  |  |  |  |  |  |  |  |  | 45.0 | 27.4 |  |
Purchase price of hedges | 21,628 | $ 46,550 |  |  |  |  |  |  |  | $ 46,550 | $ 21,628 |  |
Foreign currency forward contracts |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments, Contingencies And Litigation [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Purchase price of hedges | 29,362 | 44,311 |  |  |  |  |  |  |  | 44,311 | 29,362 |  |
EnerSys Delaware Inc and Altergy Systems Litigation | EnerSys Delaware Inc. |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments, Contingencies And Litigation [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Legal proceedings charge |  |  |  |  |  | $ 58,184 |  |  |  |  |  |  | $ 58,184
Belgium Anti-Competition Proceeding |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments, Contingencies And Litigation [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Reserves for anti-competition investigations | $ 2,038 | 1,830 |  |  |  |  |  |  |  | 1,830 | $ 2,038 |  |
Germany Anti-competition Proceedings |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments, Contingencies And Litigation [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Loss contingency, estimate of possible loss |  | $ 13,463 |  |  |  |  |  |  |  | 13,463 |  |  |
Loss contingency accrual, provision |  |  |  |  |  |  |  |  | $ 17,000 | $ 10,258 |  |  |
Minimum | Germany Anti-competition Proceedings |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments, Contingencies And Litigation [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Loss contingency, estimate of possible loss |  |  | 17,000 |  |  |  |  |  | 17,000 |  |  |  |
Maximum | Germany Anti-competition Proceedings |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments, Contingencies And Litigation [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Loss contingency, estimate of possible loss |  |  | $ 26,000 |  |  |  |  |  | $ 26,000 |  |  |  |

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