Schedule of Components of Provision for Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Income Tax Disclosure [Abstract]
Current Provision (Benefit) - Federal	$ 67,913	$ (91,304)	$ 53,570
Current Provision (Benefit) - State	9,587	3,004	9,414
Current Provision (Benefit) - Total	77,500	(88,300)	62,984
Deferred Provision (Benefit) - Federal	7,207	108,467	(726)
Deferred Provision (Benefit) - State	5,239	4,337	(1,986)
Deferred Provision (Benefit) - Total	12,446	112,804	(2,712)
Provision for Income Taxes	$ 89,946	$ 24,504	$ 60,272