Consolidated Statements of Operations - USD ($) shares in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2020	Sep. 18, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenues and other income	$ 220,600,000	$ 530,112,000	$ 1,274,883,000	$ 1,473,625,000
Expenses
Taxes other than income	16,584,000	43,531,000	93,752,000	104,670,000
General and administrative expenses	19,470,000	48,522,000	83,029,000	71,495,000
Interest, net of amounts capitalized of $1,261, $22,885, $36,671 and $37,079, respectively	1,815,000	48,267,000	81,632,000	69,688,000
Depletion, depreciation, and amortization	45,812,000	188,593,000	233,816,000	216,449,000
Commodity derivatives expense (income)	61,902,000	(102,032,000)	70,078,000	(21,087,000)
Gain on debt extinguishment	0	(18,994,000)	(155,998,000)	0
Write-down of oil and natural gas properties	1,006,000	996,658,000	0	0
Reorganization items, net	0	849,980,000	0	0
Other expenses	8,072,000	35,868,000	11,187,000	84,325,000
Total expenses	273,784,000	2,378,819,000	953,572,000	1,063,694,000
Income (loss) before income taxes	(53,184,000)	(1,848,707,000)	321,311,000	409,931,000
Income tax provision (benefit)	(2,526,000)	(416,129,000)	104,352,000	87,233,000
Net income (loss)	$ (50,658,000)	$ (1,432,578,000)	$ 216,959,000	$ 322,698,000
Net income (loss) per common share
Basic	$ (1.01)	$ (2.89)	$ 0.47	$ 0.75
Diluted	$ (1.01)	$ (2.89)	$ 0.45	$ 0.71
Weighted average common shares outstanding
Basic	50,000	495,560	459,524	432,483
Diluted	50,000	495,560	510,341	456,169
Other income
Revenues and other income	$ 4,697,000	$ 8,419,000	$ 14,523,000	$ 17,970,000
Transportation and marketing
Operating expenses	10,595,000	27,164,000	41,810,000	43,942,000
Oil, natural gas, and related product sales
Revenues and other income	201,108,000	492,101,000	1,212,020,000	1,422,589,000
Operating expenses	101,234,000	250,271,000	477,220,000	489,720,000
CO2
Revenues and other income	9,419,000	21,049,000	34,142,000	31,145,000
Operating expenses	1,976,000	2,592,000	2,922,000	2,816,000
Oil marketing
Revenues and other income	5,376,000	8,543,000	14,198,000	1,921,000
Operating expenses	$ 5,318,000	$ 8,399,000	$ 14,124,000	$ 1,676,000