Leases - Schedule of Supplemental Cash Flow Information Related to Operating Leases (Detail) - USD ($)	6 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Leases [Abstract]
Cash paid for amounts included in the measurement of operating lease liabilities	$ 7,352,000	$ 7,438,000
Operating lease liabilities arising from obtaining ROU assets	104,108,000	104,476,000
Finance lease liabilities arising from obtaining ROU assets	358,000	0
Reductions to ROU assets resulting from reductions to operating lease liabilities	$ 928,000	$ 4,073,000