Accounts and Taxes Payable and Accrued Liabilities - Accrued Liabilities (Detail) - USD ($)	Dec. 31, 2017	Mar. 31, 2017
Payables And Accruals [Abstract]
Payroll, payroll taxes and employee benefits	$ 19,261,000	$ 14,465,000
Customer deposits	41,900,000	32,471,000
Accrued professional service fees	5,682,000	4,551,000
Self-insurance accruals	3,571,000	2,835,000
Deferred revenue	13,694,000	10,096,000
Accrued rent	5,204,000	5,774,000
Other	3,656,000	3,276,000
Total accrued liabilities	$ 92,968,000	$ 73,468,000