Income Taxes - Summary of Income Tax Provision (Detail) - USD ($)	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Income Tax Disclosure [Abstract]
Current — Federal	$ 16,608,000	$ 9,212,000	$ 10,233,000
Current — State	4,587,000	2,652,000	3,121,000
Subtotal	21,195,000	11,864,000	13,354,000
Deferred — Federal	(6,809,000)	1,418,000	941,000
Deferred — State	(1,567,000)	52,000	515,000
Subtotal	(8,376,000)	1,470,000	1,456,000
Total	$ 12,819,000	$ 13,334,000	$ 14,810,000