Goodwill and Other Intangible Assets - Schedule of Changes in Carrying Amount of Goodwill by Business Segment (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Goodwill [Roll Forward]
Balance at beginning of year	$ 682,934	$ 676,715
Foreign currency translation adjustment	(12,682)	1,829
Acquisitions	50,821	4,390
Balance at end of year	721,073	682,934
Energy Systems
Goodwill [Roll Forward]
Balance at beginning of year	259,011	258,204
Foreign currency translation adjustment	(13,264)	807
Acquisitions	0	0
Balance at end of year	245,747	259,011
Motive Power
Goodwill [Roll Forward]
Balance at beginning of year	326,718	321,530
Foreign currency translation adjustment	328	798
Acquisitions	0	4,390
Balance at end of year	327,046	326,718
Specialty
Goodwill [Roll Forward]
Balance at beginning of year	97,205	96,981
Foreign currency translation adjustment	254	224
Acquisitions	50,821	0
Balance at end of year	$ 148,280	$ 97,205