CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Revenues and other:
Revenues and other	$ 101,313,000	$ 149,163,000	$ 305,069,000	$ 433,730,000
(Losses) gains on derivatives			160,222,000	(2,796,000)
Total revenues and other	89,749,000	194,672,000	462,467,000	441,276,000
Expenses and other:
Transportation expenses	1,768,000	2,067,000	5,379,000	5,935,000
Marketing expenses	326,000	398,000	1,036,000	1,670,000
General and administrative expenses	19,173,000	16,434,000	57,287,000	46,932,000
Depreciation, depletion, and amortization	35,905,000	27,664,000	108,746,000	75,904,000
Impairment of oil and gas properties	0	0	289,085,000	0
Taxes, other than income taxes	9,913,000	9,249,000	24,714,000	28,683,000
Losses (gains) on derivatives			(160,222,000)	2,796,000
Other operating expenses (income)	1,648,000	(550,000)	2,658,000	3,814,000
Total expenses and other	102,409,000	113,008,000	633,994,000	344,750,000
Other (expenses) income:
Interest expense	(8,391,000)	(8,597,000)	(25,987,000)	(26,362,000)
Other, net	(3,000)	(77,000)	(15,000)	79,000
Total other (expenses) income	(8,394,000)	(8,674,000)	(26,002,000)	(26,283,000)
Reorganization items, net	0	(170,000)	0	(426,000)
(Loss) income before income taxes	(21,054,000)	72,820,000	(197,529,000)	69,817,000
Income tax (benefit) expense	(2,190,000)	20,171,000	1,536,000	19,294,000
Net (loss) income	$ (18,864,000)	$ 52,649,000	$ (199,065,000)	$ 50,523,000
Net (loss) income per share:
Basic (in dollars per share)	$ (0.24)	$ 0.65	$ (2.50)	$ 0.62
Diluted (in dollars per share)	$ (0.24)	$ 0.65	$ (2.50)	$ 0.62
Oil, natural gas and natural gas liquids sales
Revenues and other:
Revenues and other	$ 92,239,000	$ 141,250,000	$ 284,852,000	$ 409,259,000
Expenses and other:
Cost of goods sold	45,243,000	50,957,000	136,727,000	156,765,000
Electricity sales
Revenues and other:
Revenues and other	8,744,000	7,460,000	19,089,000	22,553,000
Expenses and other:
Cost of goods sold	4,217,000	3,781,000	11,186,000	14,705,000
(Losses) gains on oil derivatives
Revenues and other:
(Losses) gains on derivatives	(11,564,000)	45,509,000	157,398,000	7,546,000
Expenses and other:
Losses (gains) on derivatives	11,564,000	(45,509,000)	(157,398,000)	(7,546,000)
Marketing revenues
Revenues and other:
Revenues and other	330,000	413,000	1,075,000	1,657,000
Other revenues
Revenues and other:
Revenues and other	0	40,000	53,000	261,000
Natural gas sales
Revenues and other:
Revenues and other	3,347,000	4,067,000	9,549,000	14,867,000
(Losses) gains on derivatives	15,784,000	(3,008,000)	2,824,000	(10,342,000)
Expenses and other:
Losses (gains) on derivatives	$ (15,784,000)	$ 3,008,000	$ (2,824,000)	$ 10,342,000