CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) (in thousands) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Cash flows from operating activities:
Net income		$ 317,401	$ 74,434
Adjustments to reconcile net income to net cash provided by operating activities:
Net gain on divestiture activity		(385,369)	(37,463)
Depletion, depreciation, amortization, and asset retirement obligation liability accretion		130,473	137,812
Abandonment and impairment of oil and gas properties		5,625	0
Stock-based compensation expense		5,412	5,455
Net derivative (gain) loss		7,529	(114,774)
Derivative settlement gain (loss)		(24,528)	7
Amortization of debt discount and deferred financing costs		3,866	4,946
Loss on extinguishment of debt		0	35
Deferred income taxes		98,366	33,225
Other, net		(2,527)	3,376
Changes in current assets and liabilities:
Accounts receivable		(4,464)	30,407
Prepaid expenses and other		755	178
Accounts payable and accrued expenses		(8,825)	(5,497)
Accrued derivative settlements		(3,579)	2,838
Net cash provided by operating activities		140,135	134,979
Cash flows from investing activities:
Net proceeds from the sale of oil and gas properties		490,780	744,333
Capital expenditures		(301,521)	(154,401)
Acquisition of proved and unproved oil and gas properties		0	(75,105)
Net cash provided by investing activities		189,259	514,827
Cash flows from financing activities:
Proceeds from credit facility		0	397,500
Repayment of credit facility		0	(397,500)
Cash paid to repurchase Senior Notes		0	(2,344)
Cash paid for extinguishment of debt		0	(13)
Other, net		0	(160)
Net cash used in financing activities		0	(2,517)
Net change in cash, cash equivalents, and restricted cash	[1]	329,394	647,289
Cash, cash equivalents, and restricted cash at beginning of period	[1]	313,943	12,372
Cash, cash equivalents, and restricted cash at end of period	[1]	643,337	659,661
Operating Activities:
Cash paid for interest, net of capitalized interest		(40,060)	(42,872)
Net cash (paid) refunded for income taxes		(106)	15
Investing activities:
Changes in capital expenditure accruals and other		60,299	27,214
Supplemental non-cash investing activities:
Carrying value of properties exchanged		0	24,544
Supplemental non-cash financing activities:
Non-cash loss on extinguishment of debt, net		0	22
Dividends declared, but not paid		$ 5,584	$ 5,563

[1] Refer to Note 1 - Summary of Significant Accounting Policies for a reconciliation of cash, cash equivalents, and restricted cash reported to the amounts reported within the accompanying condensed consolidated balance sheets (“accompanying balance sheets”).