Other Accrued Liabilities - Summary of Other Accrued Liabilities (Detail) - USD ($) $ in Thousands	Nov. 30, 2015	May. 31, 2015
Schedule of Accrued Liabilities [Line Items]
Payroll and other compensation expenses	$ 34,962	$ 35,858
Insurance accruals	6,563	5,712
Property, sales and other non-income related taxes	3,342	2,840
Lease commitments	1,737	1,703
Deferred revenue	1,193	1,116
Contingent consideration	2,800	229
Other	12,392	6,727
Total	$ 62,989	$ 54,185