Stock-Based Compensation (Schedule of Restricted Stock Awards and Stock Options) (Details) - USD ($) $ in Thousands			1 Months Ended	2 Months Ended	3 Months Ended		8 Months Ended	9 Months Ended
		Aug. 31, 2020	Sep. 30, 2020	Aug. 31, 2020	Sep. 30, 2020	Sep. 30, 2019	Aug. 31, 2020	Sep. 30, 2020	Sep. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Abstract]
Recognized stock compensation expense	[1]				$ 2,000	$ 4,500		$ 6,100	$ 13,000
Capitalized stock compensation cost for our oil and natural gas properties					0	700		0	2,000
Tax benefit on stock based compensation					$ 500	$ 1,100		$ 1,500	$ 3,200
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Acceleration of Predecessor stock compensation expense		$ 1,400	$ 0	$ 1,431			$ 1,431

[1] When the company's equity-based awards were cancelled on the Effective Date, we immediately recognized the expense for the cancelled awards of $1.4 million as reorganization costs, net.