Summary of Accrued Expenses (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Schedule of Accrued Liabilities [Line Items]
Salaries, wages, payroll taxes and benefits	$ 43,713	$ 58,692
Workers' compensation liability	66,636	66,121
Property, sales, use and other taxes	14,074	11,850
Insurance, other than workers' compensation	8,022	6,012
Accrued interest payable	11,544	4,937
Deferred revenue-current	3,330	7,229
2009 Performance Unit Awards		3,640
Other	9,360	6,148
Accrued expenses	$ 156,679	$ 164,629