Summary of Accrued Expenses (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Payables And Accruals [Abstract]
Salaries, wages, payroll taxes and benefits	$ 35,447	$ 52,956
Workers' compensation liability	74,468	77,348
Property, sales, use and other taxes	11,873	11,644
Insurance, other than workers' compensation	13,234	9,632
Accrued interest payable	13,701	7,427
Other	31,807	14,459
Accrued expenses	$ 180,530	$ 173,466