Accrued Liabilities (Accrued Liabilities) (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Accrued Liabilities, Current [Abstract]
Lease operating expenses	$ 19,923	$ 20,709
Interest	17,036	6,654
Employee costs	12,300	31,451
Taxes	11,984	3,284
Third-party credits	2,854	2,825
Other	3,945	5,248
Total accrued liabilities	$ 68,042	$ 70,171