CONDENSED CONSOLIDATED STATEMENT OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (loss)	$ 127,247	$ (114,104)
Adjustments to reconcile net income (loss) to cash provided by operating activities:
Depreciation, depletion and amortization	279,422	309,420
Impairment of oil and gas properties	68,555	0
Deferred income tax expense (benefit)	73,394	(64,294)
(Gain) loss on sale of assets	1,626	(477)
Exploratory dry hole cost	2,842	18
(Gain) loss on derivative instruments	(47,190)	8,190
Net cash received (paid) in settlement of derivative instruments	(319)	11,305
(Earnings) loss on equity method investments	2,569	(1,935)
Amortization of debt issuance costs	2,384	2,692
Stock-based compensation and other	18,198	17,963
Changes in assets and liabilities:
Accounts receivable, net	13,713	2,118
Income taxes	(6,166)	516
Inventories	(4)	1,362
Other current assets	(1,776)	(1,858)
Accounts payable and accrued liabilities	(4,339)	(17,194)
Interest payable	(311)	(2,078)
Other assets and liabilities	101	646
Net cash provided by operating activities	529,946	152,290
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(393,333)	(159,399)
Proceeds from sale of assets	1,475	49,828
Investment in equity method investments	(13,626)	(18,171)
Net cash used in investing activities	(405,484)	(127,742)
CASH FLOWS FROM FINANCING ACTIVITIES
Borrowings from debt	0	90,000
Repayments of debt	0	(567,000)
Treasury stock repurchases	(68,255)	0
Sale of common stock, net	0	995,279
Dividends paid	(32,582)	(17,582)
Tax withholdings on stock award vestings	(5,672)	(5,046)
Capitalized debt issuance costs	0	(3,223)
Other	39	0
Net cash provided by (used in) financing activities	(106,470)	492,428
Net increase in cash and cash equivalents	17,992	516,976
Cash and cash equivalents, beginning of period	498,542	514
Cash and cash equivalents, end of period	$ 516,534	$ 517,490