Fresh Start Accounting (Condensed Consolidated Balance Sheet) (Details 3) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Sep. 18, 2020	Dec. 31, 2019	Dec. 31, 2018
Fresh-Start Adjustment [Line Items]
Cash and cash equivalents	$ 3,671	$ 518	$ 45,585
Restricted cash			10,662
Accrued production receivable	143,365	91,421	112,832
Trade and other receivables, net	19,270	19,682	36,221
Derivative assets	0	187	32,635
Prepaids	9,099	14,038	12,429
Total current assets	175,405	126,846	250,364
Proved properties	1,109,011	851,208	782,233
Unevaluated properties	112,169	85,304	111,983
CO2 properties	183,369	188,288	187,346
Pipelines	224,394	133,485	132,618
Other property and equipment	93,950	86,610	97,413
Less accumulated depletion, depreciation, amortization and impairment	(181,393)	(41,095)	0
Net property and equipment	1,541,500	1,303,800	1,311,593
Operating lease right-of-use assets	19,502	20,342	1,843
Derivative assets			501
Intangible assets, net			100,083
Other assets	78,298	86,408	87,023
Total assets	1,902,953	1,634,758	1,751,407
Accounts payable and accrued liabilities	191,598	112,671	174,320
Oil and gas production payable			56,077
Derivative liabilities	134,509	53,865	8,613
Current maturities of long-term debt	0	68,008	73,563
Operating lease liabilities	4,677	1,350	728
Total current liabilities	406,683	285,059	313,301
Long-term debt	35,000	70,000	157,459
Asset retirement obligations	284,238	179,338	158,438
Derivative liabilities	0	5,087	295
Deferred tax liabilities, net	1,638	1,274	3,831
Operating lease liabilities	17,094	19,460	525
Other liabilities	22,910	20,872	22,139
Total long-term liabilities not subject to compromise			342,687
Liabilities subject to compromise			2,823,506
Common stock	50	50	50
Paid-in capital in excess of par			1,095,369
Accumulated deficit	5,344	(50,658)
Total stockholders' equity	1,135,390	1,053,668	1,095,419	$ 1,412,259	$ 1,141,777
Total liabilities and stockholders' equity	$ 1,902,953	$ 1,634,758	1,751,407
Predecessor
Fresh-Start Adjustment [Line Items]
Cash and cash equivalents			73,372
Accrued production receivable			112,832
Trade and other receivables, net			36,221
Derivative assets			32,635
Prepaids			12,968
Total current assets			268,028
Proved properties			11,723,546
Unevaluated properties			650,553
CO2 properties			1,198,515
Pipelines			2,339,864
Other property and equipment			201,565
Less accumulated depletion, depreciation, amortization and impairment			(12,864,141)
Net property and equipment			3,249,902
Operating lease right-of-use assets			1,774
Derivative assets			501
Intangible assets, net			20,405
Other assets			81,809
Total assets			3,622,419
Accounts payable and accrued liabilities			67,789
Oil and gas production payable			39,372
Derivative liabilities			8,613
Total current liabilities			115,774
Long-term debt			140,000
Asset retirement obligations			2,727
Derivative liabilities			295
Total long-term liabilities not subject to compromise			143,022
Liabilities subject to compromise			2,823,506
Common stock			510
Paid-in capital in excess of par			2,764,915
Predecessor treasury stock, at cost			(6,202)
Accumulated deficit			(2,219,106)
Total stockholders' equity			540,117
Total liabilities and stockholders' equity			3,622,419
Reorganization Adjustments
Fresh-Start Adjustment [Line Items]
Cash and cash equivalents			(27,787)
Restricted cash			10,662
Prepaids			(539)
Total current assets			(17,664)
Other assets			8,241
Total assets			(9,423)
Accounts payable and accrued liabilities			102,793
Oil and gas production payable			16,705
Current maturities of long-term debt			73,199
Operating lease liabilities			757
Total current liabilities			193,454
Long-term debt			42,610
Asset retirement obligations			180,408
Deferred tax liabilities, net			417,951
Operating lease liabilities			515
Other liabilities			3,540
Total long-term liabilities not subject to compromise			645,024
Liabilities subject to compromise			(2,823,506)
Predecessor treasury stock, at cost			6,202
Accumulated deficit			3,639,409
Total stockholders' equity			1,975,605
Total liabilities and stockholders' equity			(9,423)
Reorganization Adjustments | Predecessor Adjustment
Fresh-Start Adjustment [Line Items]
Common stock			(510)
Paid-in capital in excess of par			(2,764,915)
Reorganization Adjustments | Successor Adjustment
Fresh-Start Adjustment [Line Items]
Common stock			50
Paid-in capital in excess of par			1,095,369
Fresh Start Adjustments
Fresh-Start Adjustment [Line Items]
Proved properties			(10,941,313)
Unevaluated properties			(538,570)
CO2 properties			(1,011,169)
Pipelines			(2,207,246)
Other property and equipment			(104,152)
Less accumulated depletion, depreciation, amortization and impairment			12,864,141
Net property and equipment			(1,938,309)
Operating lease right-of-use assets			69
Intangible assets, net			79,678
Other assets			(3,027)
Total assets			(1,861,589)
Accounts payable and accrued liabilities			3,738
Current maturities of long-term debt			364
Operating lease liabilities			(29)
Total current liabilities			4,073
Long-term debt			(25,151)
Asset retirement obligations			(24,697)
Deferred tax liabilities, net			(414,120)
Operating lease liabilities			10
Other liabilities			18,599
Total long-term liabilities not subject to compromise			(445,359)
Accumulated deficit			(1,420,303)
Total stockholders' equity			(1,420,303)
Total liabilities and stockholders' equity			$ (1,861,589)