Income Taxes - Schedule of Components of Provision for Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Mar. 31, 2023
Income Tax Disclosure [Abstract]
Current Provision - Federal	$ 114,606	$ 111,690	$ 103,940
Current Provision - State	18,411	20,689	18,520
Current Provision - Total	133,017	132,379	122,460
Deferred Provision (Benefit) - Federal	(5,117)	5,607	11,321
Deferred Provision (Benefit) - State	169	2,312	(6,728)
Deferred Provision (Benefit) - Total	(4,948)	7,919	4,593
Provision for Income Taxes	$ 128,069	$ 140,298	$ 127,053