Accounts and Taxes Payable and Accrued Liabilities - Accrued Liabilities (Detail) - USD ($)	Sep. 30, 2019	Mar. 31, 2019
Payables And Accruals [Abstract]
Payroll, payroll taxes and employee benefits	$ 28,452,000	$ 23,647,000
Customer deposits	42,122,000	45,268,000
Accrued professional service fees	6,483,000	8,377,000
Self-insurance accruals	3,306,000	3,523,000
Deferred revenue	17,538,000	16,900,000
Operating lease liabilities	13,214,000	5,708,000
Other	2,169,000	2,018,000
Total accrued liabilities	$ 113,284,000	$ 105,441,000