Segment Reporting (Details)	12 Months Ended
	Dec. 31, 2020 USD ($) segment	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Segment Reporting Information [Line Items]
Number of business segments | segment	2
Revenues	$ 851,135,000	$ 1,026,204,000	$ 829,691,000
Lease bonus - mineral acreage	4,062,000	1,711,000	2,489,000
Realized gain on derivatives	38,937,000	9,482,000	2,334,000
Unrealized gain on derivatives	(32,008,000)	(53,727,000)	65,085,000
Expenses	1,383,625,000	748,190,000	536,328,000
Operating (loss) income	(521,499,000)	235,480,000	363,271,000
Assets	3,687,280,000	4,069,676,000	3,455,518,000
Capital expenditures	721,838,000	946,025,000	1,504,659,000
Depletion, depreciation and amortization	361,831,000	350,540,000	265,142,000
Impairment charge of net capitalized costs	684,743,000	0	0
Operating Segments | Exploration and Production
Segment Reporting Information [Line Items]
Lease bonus - mineral acreage	4,062,000	1,711,000	2,489,000
Realized gain on derivatives	38,937,000	9,482,000	2,334,000
Unrealized gain on derivatives	(32,008,000)	(53,727,000)	65,085,000
Expenses	1,334,378,000	621,687,000	487,539,000
Operating (loss) income	(561,559,000)	226,708,000	377,532,000
Assets	2,782,819,000	3,360,725,000	2,910,326,000
Capital expenditures	518,198,000	718,712,000	1,335,690,000
Depletion, depreciation and amortization	335,800,000	331,700,000	252,300,000
Payments to acquire productive assets		48,300,000	656,900,000
Operating Segments | Midstream
Segment Reporting Information [Line Items]
Lease bonus - mineral acreage	0	0	0
Realized gain on derivatives	0	0	0
Unrealized gain on derivatives	0	0	0
Expenses	97,599,000	130,612,000	44,098,000
Operating (loss) income	92,970,000	81,506,000	55,247,000
Assets	836,509,000	647,937,000	439,953,000
Capital expenditures	201,440,000	223,612,000	166,407,000
Depletion, depreciation and amortization	23,300,000	16,100,000	10,500,000
Income (loss) attributable to noncontrolling interest	39,600,000	35,200,000	25,600,000
Land and seismic acquisition expenditures	70,500,000
Payments to acquire productive assets	112,100,000	145,400,000	80,200,000
Corporate
Segment Reporting Information [Line Items]
Lease bonus - mineral acreage	0	0	0
Realized gain on derivatives	0	0	0
Unrealized gain on derivatives	0	0	0
Expenses	52,910,000	72,734,000	69,508,000
Operating (loss) income	(52,910,000)	(72,734,000)	(69,508,000)
Assets	67,952,000	61,014,000	105,239,000
Capital expenditures	2,200,000	3,701,000	2,562,000
Depletion, depreciation and amortization	2,700,000	2,700,000	2,400,000
Consolidations and Eliminations
Segment Reporting Information [Line Items]
Lease bonus - mineral acreage	0	0	0
Realized gain on derivatives	0	0	0
Unrealized gain on derivatives	0	0	0
Expenses	(101,262,000)	(76,843,000)	(64,817,000)
Operating (loss) income	0	0	0
Assets	0	0	0
Capital expenditures	0	0	0
Oil and natural gas revenues
Segment Reporting Information [Line Items]
Revenues	744,461,000	892,325,000	800,700,000
Oil and natural gas revenues | Operating Segments | Exploration and Production
Segment Reporting Information [Line Items]
Revenues	741,092,000	886,127,000	794,261,000
Oil and natural gas revenues | Operating Segments | Midstream
Segment Reporting Information [Line Items]
Revenues	3,369,000	6,198,000	6,439,000
Oil and natural gas revenues | Corporate
Segment Reporting Information [Line Items]
Revenues	0	0	0
Oil and natural gas revenues | Consolidations and Eliminations
Segment Reporting Information [Line Items]
Revenues	0	0	0
Third-party midstream services revenues
Segment Reporting Information [Line Items]
Revenues	64,932,000	59,110,000	21,920,000
Third-party midstream services revenues | Operating Segments | Exploration and Production
Segment Reporting Information [Line Items]
Revenues	0	0	0
Third-party midstream services revenues | Operating Segments | Midstream
Segment Reporting Information [Line Items]
Revenues	166,194,000	135,953,000	86,737,000
Third-party midstream services revenues | Corporate
Segment Reporting Information [Line Items]
Revenues	0	0	0
Third-party midstream services revenues | Consolidations and Eliminations
Segment Reporting Information [Line Items]
Revenues	(101,262,000)	(76,843,000)	(64,817,000)
Sales of purchased natural gas
Segment Reporting Information [Line Items]
Revenues	41,742,000	74,769,000	7,071,000
Sales of purchased natural gas | Operating Segments | Exploration and Production
Segment Reporting Information [Line Items]
Revenues	20,736,000	4,802,000	902,000
Sales of purchased natural gas | Operating Segments | Midstream
Segment Reporting Information [Line Items]
Revenues	21,006,000	69,967,000	6,169,000
Sales of purchased natural gas | Corporate
Segment Reporting Information [Line Items]
Revenues	0	0	0
Sales of purchased natural gas | Consolidations and Eliminations
Segment Reporting Information [Line Items]
Revenues	$ 0	$ 0	$ 0