CONSOLIDATED STATEMENTS OF CASH FLOWS (in thousands) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities:
Net income (loss)	$ (187,001)	$ 508,407	$ (160,843)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Net (gain) loss on divestiture activity	(862)	(426,917)	131,028
Depletion, depreciation, amortization, and asset retirement obligation liability accretion	823,798	665,313	557,036
Impairment of oil and gas properties	33,842	49,889	16,078
Stock-based compensation expense	24,318	23,908	22,700
Net derivative (gain) loss	97,539	(161,832)	26,414
Derivative settlement gain (loss)	39,222	(135,803)	21,234
Amortization of debt discount and deferred financing costs	15,474	15,258	16,276
Loss on extinguishment of debt	0	26,740	35
Deferred income taxes	(41,835)	141,708	(192,066)
Other, net	2,220	287	7,885
Changes in current assets and liabilities:
Accounts receivable	(39,556)	(20,775)	20,410
Prepaid expenses and other	6,130	(729)	(1,953)
Accounts payable and accrued expenses	50,278	35,175	51,156
Net cash provided by operating activities	823,567	720,629	515,390
Cash flows from investing activities:
Net proceeds from the sale of oil and gas properties	13,059	748,509	776,719
Capital expenditures	(1,023,769)	(1,303,188)	(888,353)
Acquisition of proved and unproved oil and gas properties	(2,581)	(33,255)	(89,896)
Net cash used in investing activities	(1,013,291)	(587,934)	(201,530)
Cash flows from financing activities:
Proceeds from credit facility	1,589,000	0	406,000
Repayment of credit facility	(1,466,500)	0	(406,000)
Net proceeds from Senior Notes	0	492,079	0
Cash paid to repurchase Senior Notes, including premium	0	(845,002)	(2,357)
Net proceeds from sale of common stock	3,209	3,187	2,623
Dividends paid	(11,254)	(11,191)	(11,144)
Other, net	(2,686)	(7,746)	(1,411)
Net cash provided by (used in) financing activities	111,769	(368,673)	(12,289)
Net change in cash, cash equivalents, and restricted cash	(77,955)	(235,978)	301,571
Cash, cash equivalents, and restricted cash at beginning of period	77,965	313,943	12,372
Cash, cash equivalents, and restricted cash at end of period	10	77,965	313,943
Supplemental Cash Flow Information - Operating Activities [Abstract]
Cash paid for interest, net of capitalized interest	(141,902)	(150,727)	(164,097)
Net cash (paid) refunded for income taxes	6,109	(2,995)	(5,986)
Supplemental Cash Flow Information - Investing Activities [Abstract]
Changes in capital expenditure accruals and other	(24,289)	(2,774)	7,309
Supplemental Cash Flow Information - Non-Cash Investing Activities [Abstract]
Carrying value of properties exchanged	73,442	95,121	293,963
Supplemental Cash Flow Information - Non-Cash Financing Activities [Abstract]
Non-cash loss on extinguishment of debt, net	$ 0	$ 6,334	$ 22