CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating Revenues
Total operating revenues	$ 452,659	$ 453,017	$ 252,839
Operating Expenses
Production tax expense	23,541	36,762	14,476
Exploration expense	143	70	83
Impairment and abandonment expense	9,642	719	49,553
(Gain) loss on sale of properties	2,901	1,046	(92)
Depreciation, depletion and amortization	321,276	228,480	159,964
Unused commitments	17,706	18,187	18,231
General and administrative expense	44,759	45,130	42,476
Merger transaction expense	4,492	7,991	8,749
Other operating expenses, net	402	1,273	(1,514)
Total operating expenses	473,343	372,152	318,764
Operating Income (Loss)	(20,684)	80,865	(65,925)
Other Income and Expense:
Interest and other income	791	1,793	1,359
Interest expense	(58,100)	(52,703)	(57,710)
Commodity derivative gain (loss)	(98,953)	93,349	(9,112)
Gain (loss) on extinguishment of debt	0	(257)	(8,239)
Total other income (expense)	(156,262)	42,182	(73,702)
Income (Loss) before Income Taxes	(176,946)	123,047	(139,627)
(Provision for) Benefit from Income Taxes	42,116	(1,827)	1,402
Net income (loss)	$ (134,830)	$ 121,220	$ (138,225)
Net Income (Loss) Per Common Share, Basic (in dollars per share)	$ (0.64)	$ 0.64	$ (1.80)
Net Income (Loss) Per Common Share, Diluted (in dollars per share)	$ (0.64)	$ 0.64	$ (1.80)
Weighted Average Common Shares Outstanding, Basic (in shares)	210,391,669	188,299,074	76,858,815
Weighted Average Common Shares Outstanding, Diluted (in shares)	210,391,669	189,241,036	76,858,815
Oil, gas and NGL production
Operating Revenues
Production and other revenues	$ 452,274	$ 452,917	$ 251,215
Other operating revenues, net
Operating Revenues
Production and other revenues	385	100	1,624
Lease operating expense
Operating Expenses
Cost of goods and services	37,796	27,850	24,223
Gathering, transportation and processing expense
Operating Expenses
Cost of goods and services	$ 10,685	$ 4,644	$ 2,615