CONDENSED CONSOLIDATED STATEMENT OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (loss)	$ 144,834	$ (124,364)
Adjustments to reconcile net income (loss) to cash provided by operating activities:
Depreciation, depletion and amortization	425,689	448,910
Impairment of oil and gas properties	68,555	0
Deferred income tax expense (benefit)	89,731	(59,413)
Loss on sale of assets	13,498	768
Exploratory dry hole cost	2,842	18
(Gain) loss on derivative instruments	(46,353)	1,286
Net cash received in settlement of derivative instruments	3,587	3,204
(Earnings) loss on equity method investments	3,986	(208)
Amortization of debt issuance costs	3,579	3,888
Stock-based compensation and other	26,011	23,051
Changes in assets and liabilities:
Accounts receivable, net	29,276	(1,135)
Income taxes	(16,665)	(11,235)
Inventories	(2,100)	2,860
Other current assets	(896)	(917)
Accounts payable and accrued liabilities	(5,133)	(12,174)
Interest payable	(15,318)	(17,618)
Other assets and liabilities	(6,076)	784
Net cash provided by operating activities	719,047	257,705
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(586,813)	(245,033)
Proceeds from sale of assets	32,711	49,068
Investment in equity method investments	(23,382)	(24,176)
Net cash used in investing activities	(577,484)	(220,141)
CASH FLOWS FROM FINANCING ACTIVITIES
Borrowings from debt	0	90,000
Repayments of debt	0	(587,000)
Treasury stock repurchases	(68,255)	0
Sale of common stock, net	0	995,279
Dividends paid	(55,707)	(26,885)
Tax withholdings on stock award vestings	(5,929)	(5,056)
Capitalized debt issuance costs	0	(3,223)
Other	42	0
Net cash provided by (used in) financing activities	(129,849)	463,115
Net increase in cash and cash equivalents	11,714	500,679
Cash and cash equivalents, beginning of period	498,542	514
Cash and cash equivalents, end of period	$ 510,256	$ 501,193