CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenues and other:
Revenues and other	$ 75,720,000	$ 142,790,000	$ 203,756,000	$ 284,568,000
(Losses) gains on derivatives			156,002,000	(45,297,000)
Total revenues and other	33,453,000	170,066,000	372,718,000	246,605,000
Expenses and other:
Transportation expenses	1,789,000	1,694,000	3,611,000	3,867,000
Marketing expenses	280,000	421,000	710,000	1,272,000
General and administrative expenses	18,777,000	16,158,000	38,114,000	30,498,000
Depreciation, depletion, and amortization	37,512,000	23,654,000	72,841,000	48,240,000
Impairment of oil and gas properties	0	0	289,085,000	0
Taxes, other than income taxes	10,449,000	11,348,000	14,801,000	19,434,000
Losses (gains) on derivatives			(156,002,000)	45,297,000
Other operating (income) expenses	(1,192,000)	3,119,000	1,010,000	4,364,000
Total expenses and other	112,295,000	116,886,000	531,585,000	231,740,000
Other (expenses) income:
Interest expense	(8,676,000)	(8,961,000)	(17,596,000)	(17,766,000)
Other, net	(6,000)	0	(12,000)	155,000
Total other (expenses) income	(8,682,000)	(8,961,000)	(17,608,000)	(17,611,000)
Reorganization items, net	0	(26,000)	0	(257,000)
(Loss) income before income taxes	(87,524,000)	44,193,000	(176,475,000)	(3,003,000)
Income tax (benefit) expense	(22,623,000)	12,221,000	3,726,000	(877,000)
Net (loss) income	$ (64,901,000)	$ 31,972,000	$ (180,201,000)	$ (2,126,000)
Net (loss) income per share:
Basic (in dollars per share)	$ (0.81)	$ 0.39	$ (2.26)	$ (0.03)
Diluted (in dollars per share)	$ (0.81)	$ 0.39	$ (2.26)	$ (0.03)
Oil, natural gas and natural gas liquids sales
Revenues and other:
Revenues and other	$ 70,515,000	$ 136,908,000	$ 192,613,000	$ 268,010,000
Expenses and other:
Cost of goods sold	40,733,000	47,879,000	91,485,000	105,807,000
Electricity sales
Revenues and other:
Revenues and other	4,884,000	5,364,000	10,345,000	15,093,000
Expenses and other:
Cost of goods sold	3,022,000	3,164,000	6,968,000	10,924,000
(Losses) gains on oil derivatives
Revenues and other:
(Losses) gains on derivatives	(42,267,000)	27,276,000	168,962,000	(37,963,000)
Expenses and other:
Losses (gains) on derivatives	42,267,000	(27,276,000)	(168,962,000)	37,963,000
Marketing revenues
Revenues and other:
Revenues and other	292,000	414,000	745,000	1,244,000
Other revenues
Revenues and other:
Revenues and other	29,000	104,000	53,000	221,000
Natural gas sales
Revenues and other:
Revenues and other	2,834,000	4,086,000	6,202,000	10,800,000
(Losses) gains on derivatives	(925,000)	(9,449,000)	(12,960,000)	(7,334,000)
Expenses and other:
Losses (gains) on derivatives	$ 925,000	$ 9,449,000	$ 12,960,000	$ 7,334,000