Accrued Expenses and Other Current Liabilities (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Other Liabilities Disclosure [Abstract]
Payroll and related employee benefits	$ 36,447	$ 32,209
Accrued insurance	43,014	29,253
Performance guarantees	37,255	32,314
Loss job reserves	12,429	10,082
Other	37,645	46,915
Total	$ 166,790	$ 150,773