Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net income (loss)	$ 430,560,000	$ 435,152,000	$ (979,709,000)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Accretion expense	4,119,000	1,611,000	1,057,000
Depletion, depreciation and amortization	486,664,000	364,629,000	245,974,000
Impairment of oil and gas properties	0	0	715,495,000
Stock-based compensation expense	6,799,000	6,369,000	7,351,000
(Income) loss from equity investments	(49,625,000)	18,513,000	37,788,000
Gain on debt extinguishment	0	0	(1,108,000)
Change in fair value of derivative instruments	65,051,000	(188,802,000)	323,303,000
Deferred income tax expense	1,208,000	1,690,000	18,188,000
Amortization of loan costs	6,121,000	5,011,000	3,660,000
Amortization of note discount and premium	0	0	(1,716,000)
Gain on sale of equity method investments	(124,768,000)	(12,523,000)	(3,391,000)
Distributions from equity method investments	3,206,000	0	0
Changes in operating assets and liabilities:
Increase in accounts receivable—oil and natural gas sales	(63,427,000)	(35,879,000)	(76,269,000)
Decrease (increase) in accounts receivable—joint interest and other	12,943,000	(9,573,000)	11,380,000
Decrease in accounts receivable—related parties		16,000	0
Increase in prepaid expenses and other current assets	(5,695,000)	(1,777,000)	(3,734,000)
Decrease (increase) in other assets	4,066,000	(7,866,000)	0
(Decrease) increase in accounts payable, accrued liabilities and other	(24,015,000)	106,375,000	43,763,000
Settlement of asset retirement obligation	(719,000)	(3,057,000)	(4,189,000)
Net cash provided by operating activities	752,488,000	679,889,000	337,843,000
Cash flows from investing activities:
Deductions to cash held in escrow	0	8,000	8,000
Additions to other property and equipment	(7,870,000)	(19,372,000)	(33,152,000)
Acquisitions of oil and natural gas properties	0	(1,348,657,000)	0
Additions to oil and natural gas properties	(865,300,000)	(1,064,678,000)	(724,925,000)
Proceeds from sale of oil and gas properties	5,114,000	4,866,000	45,812,000
Proceeds from sale of other property and equipment	351,000	1,569,000	0
Proceeds from sale of other property and equipment	226,487,000	0	0
Contributions to equity method investments	(2,319,000)	(55,280,000)	(26,472,000)
Distributions from equity method investments	446,000	7,376,000	18,147,000
Net cash used in investing activities	(643,091,000)	(2,474,168,000)	(720,582,000)
Cash flows from financing activities:
Principal payments on borrowings	(220,575,000)	(365,276,000)	(87,685,000)
Borrowings on line of credit	265,000,000	365,000,000	86,000,000
Proceeds from bond issuance	0	450,000,000	1,250,000,000
Repayment of bonds	0	0	(624,561,000)
Borrowings on term loan	0	2,951,000	21,049,000
Debt issuance costs and loan commitment fees	(831,000)	(14,350,000)	(24,718,000)
Payments on repurchase of stock	(200,251,000)	0	0
Proceeds from issuance of common stock, net of offering costs and exercise of stock options		(5,364,000)	1,110,555,000
Net cash (used in) provided by financing activities	(156,657,000)	432,961,000	1,730,640,000
Net (decrease) increase in cash, cash equivalents and restricted cash	(47,260,000)	(1,361,318,000)	1,347,901,000
Cash, cash equivalents and restricted cash at beginning of period	99,557,000	1,460,875,000	112,974,000
Cash, cash equivalents and restricted cash at end of period	52,297,000	99,557,000	1,460,875,000
Supplemental disclosure of cash flow information:
Interest payments	126,342,000	101,958,000	68,966,000
Income tax receipts	0	(1,105,000)	(19,770,000)
Supplemental disclosure of non-cash transactions:
Capitalized stock-based compensation	4,533,000	4,246,000	4,900,000
Asset retirement obligation capitalized	1,452,000	42,270,000	10,971,000
Interest capitalized	4,470,000	9,470,000	9,148,000
Foreign currency translation (loss) gain on equity method investments	$ (15,487,000)	$ 12,519,000	$ 3,468,000