Fresh Start Accounting (Other Property Schedule) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Sep. 01, 2020	Aug. 31, 2020	Dec. 31, 2019
Drilling equipment	$ 63,687	$ 63,458	$ 1,285,024	$ 1,295,713
Gas gathering and processing equipment	251,404	250,098	833,788	824,699
Saltwater disposal systems	0	0	43,541	69,692
Land and building	32,635	32,635	59,080	59,080
Transportation equipment	3,130	3,314	15,577	29,723
Other	9,961	9,958	57,427	57,992
Property, plant and equipment, gross, total	600,989			8,931,355
Less accumulated depletion, amortization, and impairment	(54,189)			(6,978,669)
Net property and equipment	$ 546,800			$ 1,952,686
Non Oil and Natural Gas
Property, plant and equipment, gross, total		359,463	2,294,437
Less accumulated depletion, amortization, and impairment		0	(1,618,754)
Net property and equipment		$ 359,463	$ 675,683