Accounts and Income Taxes Payable and Accrued Liabilities - Accrued Liabilities (Detail) - USD ($)	Mar. 31, 2021	Mar. 31, 2020
Payables And Accruals [Abstract]
Payroll, payroll taxes and employee benefits	$ 43,998,000	$ 26,024,000
Customer deposits	56,498,000	48,991,000
Accrued professional service fees	7,016,000	5,919,000
Self-insurance accruals	3,704,000	3,248,000
Deferred revenue	22,514,000	17,645,000
Operating lease liabilities	12,765,000	13,223,000
Other	2,391,000	2,276,000
Total accrued liabilities	$ 148,886,000	$ 117,326,000