Leases - Schedule of Supplemental Cash Flow Information Related to Operating Leases (Detail) - USD ($)	6 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Leases [Abstract]
Cash paid for amounts included in the measurement of operating lease liabilities	$ 7,557,000	$ 7,352,000
Operating lease liabilities arising from obtaining ROU assets	58,752,000	104,108,000
Finance lease liabilities arising from obtaining ROU assets	358,000	358,000
Reductions to ROU assets resulting from reductions to operating lease liabilities	$ 3,694,000	$ 928,000