Stockholders' Equity - Noncontrolling Interests (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Jan. 01, 2017	Dec. 27, 2015	Jan. 01, 2017	Dec. 27, 2015
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			$ 5,304
Net earnings attributable to noncontrolling interests	$ (860)	$ 264	1,937	$ 974
Unrealized gain (loss) on derivative instrument, Net-of-Tax Amount	(903)	2,991	(1,566)	2,402
Amount reclassified out of AOCI, net of tax	198	292	747	930
Total other comprehensive loss, net of tax	(54,573)	(8,786)	(73,764)	(21,240)
Total comprehensive (loss) income	(17,478)	$ 29,428	50,743	104,676
Dividends paid to stockholders			(22,800)	(23,322)
Option proceeds			5	$ 139
Ending balance	$ 4,923		$ 4,923
Dividends declared (in dollars per share)	$ 0.175	$ 0.175	$ 0.525	$ 0.525
Equity Attributable to EnerSys Stockholders
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			$ 1,013,131
Net earnings attributable to noncontrolling interests			126,444
Unrealized gain (loss) on derivative instrument, Net-of-Tax Amount			411
Amount reclassified out of AOCI, net of tax			747
Foreign currency translation adjustment, Net-of Tax Amount			(74,516)
Total other comprehensive loss, net of tax			(73,358)
Total comprehensive (loss) income			53,086
Dividends paid to stockholders			(22,800)
Option proceeds			11,143
Ending balance	$ 1,054,560		1,054,560
Nonredeemable Noncontrolling Interests
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			5,304
Net earnings attributable to noncontrolling interests			84
Unrealized gain (loss) on derivative instrument, Net-of-Tax Amount			0
Amount reclassified out of AOCI, net of tax			0
Foreign currency translation adjustment, Net-of Tax Amount			(465)
Total other comprehensive loss, net of tax			(465)
Total comprehensive (loss) income			(381)
Dividends paid to stockholders			0
Option proceeds			0
Ending balance	4,923		4,923
Total Equity
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			1,018,435
Net earnings attributable to noncontrolling interests			126,528
Unrealized gain (loss) on derivative instrument, Net-of-Tax Amount			411
Amount reclassified out of AOCI, net of tax			747
Foreign currency translation adjustment, Net-of Tax Amount			(74,981)
Total other comprehensive loss, net of tax			(73,823)
Total comprehensive (loss) income			52,705
Dividends paid to stockholders			(22,800)
Option proceeds			11,143
Ending balance	$ 1,059,483		$ 1,059,483