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