Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Accrued Liabilities, Current [Abstract]
High deductible insurance	$ 6,580	$ 7,960
Wages and bonus	16,820	13,670
Other	27,080	38,520
Total accrued liabilities	$ 50,480	$ 60,150