Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flows from operating activities:
Net income (loss)	$ 789,447	$ (399,679)	$ (353,668)
Adjustments to reconcile net income (loss) to cash provided by operating activities:
Depreciation, depletion, amortization and accretion	1,670,838	1,709,567	1,746,454
Property impairments	237,370	237,292	402,131
Non-cash (gain) loss on derivatives, net	(58,031)	156,621	(21,532)
Stock-based compensation	45,868	48,098	51,834
Tax benefit from US tax reform legislation	(713,655)	0	0
Provision (benefit) for deferred income taxes from operations	88,056	(209,836)	(181,441)
Tax deficiency (benefit) from stock-based compensation	0	9,828	(13,177)
Dry hole costs	176	4,866	8,381
Litigation settlement	59,600	0	0
Net gain on sale of assets and other	(55,124)	(304,489)	(23,149)
Loss on extinguishment of debt	554	26,055	0
Other, net	12,592	9,812	12,646
Changes in assets and liabilities:
Accounts receivable	(329,811)	(158,383)	524,973
Inventories	14,517	(17,836)	7,997
Other current assets	1,038	968	65,493
Accounts payable trade	137,339	(14,404)	(201,434)
Revenues and royalties payable	158,982	30,455	(85,754)
Accrued liabilities and other	21,368	(883)	(84,056)
Other noncurrent assets and liabilities	(2,018)	(2,133)	1,403
Net cash provided by operating activities	2,079,106	1,125,919	1,857,101
Cash flows from investing activities:
Exploration and development	(1,931,942)	(1,154,131)	(3,042,747)
Purchase of producing crude oil and natural gas properties	(8,446)	(5,008)	(557)
Purchase of other property and equipment	(12,810)	(5,375)	(36,951)
Proceeds from sale of assets	144,353	631,549	34,008
Net cash used in investing activities	(1,808,845)	(532,965)	(3,046,247)
Cash flows from financing activities:
Credit facility borrowings	1,302,000	1,691,000	2,001,000
Repayment of credit facility	(2,019,000)	(1,639,000)	(1,313,000)
Proceeds from issuance of Senior Notes	990,000	0	0
Redemption of Senior Notes	0	(600,000)	0
Premium on redemption of Senior Notes	0	(19,168)	0
Proceeds from other debt	0	0	500,000
Repayment of other debt	(502,214)	(2,144)	(2,078)
Debt issuance costs	(1,999)	(40)	(4,597)
Repurchase of restricted stock for tax withholdings	(11,821)	(8,593)	(7,313)
Tax (deficiency) benefit from stock-based compensation	0	(9,828)	13,177
Net cash (used in) provided by financing activities	(243,034)	(587,773)	1,187,189
Effect of exchange rate on cash and cash equivalents	32	(1)	(10,961)
Net change in cash and cash equivalents	27,259	5,180	(12,918)
Cash and cash equivalents at beginning of period	16,643	11,463	24,381
Cash and cash equivalents at end of period	$ 43,902	$ 16,643	$ 11,463