Accrued Liabilities (Accrued Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Sep. 01, 2020	Dec. 31, 2019
Accrued Liabilities [Abstract]
Employee costs	$ 8,878		$ 17,832
Lease operating expenses	6,405		9,200
Taxes	2,324		3,450
Litigation settlements	2,070	$ 45,000	0
Interest payable	884		6,562
Third-party credits	0		3,691
Other	1,182		5,827
Total accrued liabilities	$ 21,743		$ 46,562