Accrued Liabilities (Accrued Liabilities) (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Accrued Liabilities [Abstract]
Interest payable	$ 17,171	$ 6,562
Employee costs	8,093	17,832
Lease operating expenses	8,127	9,200
Taxes	3,141	3,450
Third-party credits	2,292	3,691
Other	3,006	5,827
Total accrued liabilities	$ 41,830	$ 46,562