Accrued Liabilities (Accrued Liabilities) (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Accrued Liabilities, Current [Abstract]
Interest payable	$ 16,991	$ 6,321
Lease operating expenses	16,408	17,220
Employee costs	7,237	12,641
Taxes	5,780	3,767
Third-party credits	3,966	3,326
Other	2,472	3,643
Total accrued liabilities	$ 52,854	$ 46,918