CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Statement of Cash Flows [Abstract]
Net loss	$ (515,891)	$ (110,566)
Adjustments to reconcile net loss to net cash provided by operating activities:
Net (gain) loss on divestiture activity	18,975	(36,082)
Depletion, depreciation, amortization, and asset retirement obligation liability accretion	425,227	437,105
Exploratory dry hole expense	(24)	22,896
Impairment of proved properties	269,785	68,440
Abandonment and impairment of unproved properties	2,349	17,446
Stock-based compensation expense	13,915	13,215
Change in Net Profits Plan liability	1,865	(8,810)
Derivative gain (loss)	149,123	(73,238)
Derivative settlement gain	248,738	274,024
Amortization of deferred financing costs	1,930	3,892
Non-cash (gain) loss on extinguishment of debt, net	(15,722)	4,123
Deferred income taxes	(291,014)	(84,556)
Plugging and abandonment	(2,716)	(3,386)
Other, net	676	(434)
Changes in current assets and liabilities:
Accounts receivable	(11,220)	38,951
Prepaid expenses and other	8,487	2,933
Accounts payable and accrued expenses	(61,727)	(34,040)
Accrued derivative settlements	14,117	17,595
Net cash provided by operating activities	256,873	549,508
Cash flows from investing activities:
Net proceeds from the sale of oil and gas properties	12,967	334,988
Capital expenditures	(345,570)	(974,130)
Acquisition of proved and unproved oil and gas properties	(17,751)	(6,588)
Other, net	(900)	(996)
Net Cash Used in Investing Activities	(351,254)	(646,726)
Cash flows from financing activities:
Proceeds from credit facility	585,000	1,230,500
Repayment of credit facility	(456,500)	(1,274,500)
Debt issuance costs related to credit facility	(3,132)	0
Net proceeds from Senior Notes	0	491,557
Cash paid to repurchase Senior Notes	(29,904)	(350,000)
Proceeds from sale of common stock	2,354	3,157
Payments of Ordinary Dividends, Common Stock	(3,404)	(3,373)
Other, net	(33)	(161)
Net Cash Provided by Financing Activities	94,381	97,180
Net change in cash and cash equivalents	0	(38)
Cash and cash equivalents at beginning of period	18	120
Cash and cash equivalents at end of period	18	82
Supplemental schedule of additional cash flow information and non-cash activities:
Cash paid for interest, net of capitalized interest	63,590	64,899
Net cash (refunded) paid for income taxes	$ (4,564)	$ 380