Accounts and Taxes Payable and Accrued Liabilities - Accrued Liabilities (Detail) - USD ($)	Sep. 30, 2018	Mar. 31, 2018
Payables And Accruals [Abstract]
Payroll, payroll taxes and employee benefits	$ 24,835,000	$ 15,100,000
Customer deposits	41,333,000	35,496,000
Accrued professional service fees	5,814,000	5,782,000
Self-insurance accruals	3,642,000	3,627,000
Deferred revenue	16,956,000	15,316,000
Accrued rent	5,783,000	6,147,000
Other	3,493,000	3,068,000
Total accrued liabilities	$ 101,856,000	$ 84,536,000