Accrued Liabilities (Accrued Liabilities) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Accrued Liabilities, Current [Abstract]
Interest payable	$ 17,360	$ 6,524
Lease operating expenses	10,627	10,075
Employee costs	8,562	15,394
Taxes	4,461	2,219
Third-party credits	2,458	2,998
Other	2,944	2,441
Total accrued liabilities	$ 46,412	$ 39,651