Quarterly Financial Data (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2021	Jan. 03, 2021	Oct. 04, 2020	Jul. 05, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 813,539	$ 751,067	$ 708,402	$ 704,924	$ 781,803	$ 763,698	$ 762,137	$ 780,230	$ 2,977,932	$ 3,087,868	$ 2,808,017
Gross profit	197,301	189,312	177,560	174,977	200,796	185,241	197,317	201,512	739,150	784,866	693,026
Operating earnings	51,669	56,071	55,415	53,220	20,065	43,084	58,710	68,336	216,375	190,195	212,465
Net earnings	33,836	38,624	35,731	35,183	(1,523)	27,305	62,698	48,636	143,374	137,116	160,627
Net earnings attributable to EnerSys stockholders	$ 33,836	$ 38,624	$ 35,731	$ 35,183	$ (1,523)	$ 27,305	$ 62,698	$ 48,636	$ 143,374	$ 137,116	$ 160,239
Basic earnings per common share attributable to EnerSys stockholders (usd per share)	$ 0.79	$ 0.91	$ 0.84	$ 0.83	$ (0.04)	$ 0.65	$ 1.48	$ 1.14	$ 3.37	$ 3.23	$ 3.79
Diluted earnings per common share attributable to EnerSys stockholders (usd per share)	$ 0.78	$ 0.89	$ 0.83	$ 0.82	$ (0.04)	$ 0.64	$ 1.47	$ 1.13	$ 3.32	$ 3.20	$ 3.73