Segment Reporting (Details)	12 Months Ended
	Dec. 31, 2018 USD ($) segment	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Segment Reporting Information [Line Items]
Number of business segments | segment	2
Revenues	$ 829,691,000
Lease bonus - mineral acreage	2,489,000	$ 0	$ 0
Realized gain on derivatives	2,334,000	(4,321,000)	9,286,000
Unrealized gain on derivatives	65,085,000	9,715,000	(41,238,000)
Expenses	536,328,000	383,435,000	441,589,000
Operating income (loss)	363,271,000	160,841,000	(177,167,000)
Assets	3,455,518,000	2,145,690,000	1,464,665,000
Capital expenditures	1,504,659,000	872,958,000	454,360,000
Depletion, depreciation and amortization	265,142,000	177,502,000	122,048,000
Income (loss) attributable to noncontrolling interest	25,557,000	12,140,000	364,000
Impairment charge of net capitalized costs	0	0	158,633,000
Operating Segments | Exploration and Production
Segment Reporting Information [Line Items]
Lease bonus - mineral acreage	2,489,000
Realized gain on derivatives	2,334,000	(4,321,000)	9,286,000
Unrealized gain on derivatives	65,085,000	9,715,000	(41,238,000)
Expenses	487,539,000	333,923,000	391,098,000
Operating income (loss)	377,532,000	197,333,000	(133,538,000)
Assets	2,910,326,000	1,768,393,000	1,098,525,000
Capital expenditures	1,335,690,000	753,157,000	379,881,000
Depletion, depreciation and amortization	252,300,000	170,500,000	118,400,000
Impairment charge of net capitalized costs			158,600,000
Operating Segments | Midstream
Segment Reporting Information [Line Items]
Lease bonus - mineral acreage	0
Realized gain on derivatives	0	0
Unrealized gain on derivatives	0	0
Expenses	44,098,000	23,420,000	8,254,000
Operating income (loss)	55,247,000	26,439,000	12,372,000
Assets	439,953,000	257,871,000	140,459,000
Capital expenditures	166,407,000	114,113,000	67,566,000
Depletion, depreciation and amortization	10,500,000	5,200,000	2,700,000
Income (loss) attributable to noncontrolling interest	25,600,000	12,100,000	400,000
Land and seismic acquisition expenditures	656,900,000
Payments to acquire productive assets	80,200,000	54,900,000
Corporate
Segment Reporting Information [Line Items]
Lease bonus - mineral acreage	0
Realized gain on derivatives	0	0
Unrealized gain on derivatives	0	0
Expenses	69,508,000	62,931,000	56,001,000
Operating income (loss)	(69,508,000)	(62,931,000)	(56,001,000)
Assets	105,239,000	119,426,000	225,681,000
Capital expenditures	2,562,000	5,688,000	6,913,000
Depletion, depreciation and amortization	2,400,000	1,700,000	900,000
Consolidations and Eliminations
Segment Reporting Information [Line Items]
Lease bonus - mineral acreage	0
Realized gain on derivatives	0	0
Unrealized gain on derivatives	0	0
Expenses	(64,817,000)	(36,839,000)	(13,764,000)
Assets	0	0	0
Capital expenditures	0	0	0
Oil and natural gas revenues
Segment Reporting Information [Line Items]
Revenues	800,700,000	528,684,000	291,156,000
Oil and natural gas revenues | Operating Segments | Exploration and Production
Segment Reporting Information [Line Items]
Revenues	794,261,000	525,862,000	289,512,000
Oil and natural gas revenues | Operating Segments | Midstream
Segment Reporting Information [Line Items]
Revenues	6,439,000	2,822,000	1,644,000
Third-party midstream services revenues
Segment Reporting Information [Line Items]
Revenues	21,920,000	10,198,000	5,218,000
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	86,737,000	47,037,000	18,982,000
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	(64,817,000)	(36,839,000)	(13,764,000)
Sales of purchased natural gas
Segment Reporting Information [Line Items]
Revenues	7,071,000	$ 0	$ 0
Sales of purchased natural gas | Operating Segments | Exploration and Production
Segment Reporting Information [Line Items]
Revenues	902,000
Sales of purchased natural gas | Operating Segments | Midstream
Segment Reporting Information [Line Items]
Revenues	6,169,000
Sales of purchased natural gas | Corporate
Segment Reporting Information [Line Items]
Revenues	0
Sales of purchased natural gas | Consolidations and Eliminations
Segment Reporting Information [Line Items]
Revenues	$ 0