CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Statement of Cash Flows [Abstract]
Net income (loss)	$ (110,566)	$ 125,387
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Gain on divestiture activity	36,082	5,484
Depletion, depreciation, amortization, and asset retirement obligation liability accretion	437,105	364,996
Exploratory dry hole expense	22,896	6,459
Impairment of proved properties	68,440	0
Abandonment and impairment of unproved properties	17,446	2,965
Stock-based compensation expense	13,215	14,341
Change in Net Profits Plan liability	(8,810)	(8,881)
Derivative (gain) loss	(73,238)	224,131
Derivative cash settlements	291,619	(62,620)
Amortization of deferred financing costs	3,892	2,954
Non-cash loss on extinguishment of debt	4,123	0
Deferred income taxes	(84,556)	73,911
Plugging and abandonment	(3,386)	(3,219)
Other, net	(434)	(4,827)
Changes in current assets and liabilities:
Accounts receivable	38,951	(2,558)
Prepaid expenses and other	2,933	1,302
Accounts payable and accrued expenses	(34,040)	(13,704)
Net Cash Provided by Operating Activities	549,508	715,153
Proceeds from Sale of Oil and Gas Property and Equipment	334,988	46,821
Cash flows from investing activities:
Capital expenditures	(974,130)	(778,580)
Acquisition of proved and unproved oil and gas properties	(6,588)	(98,619)
Other, net	(996)	(2,257)
Net cash used in investing activities	(646,726)	(832,635)
Cash flows from financing activities:
Proceeds from credit facility	1,230,500	0
Repayment of credit facility	(1,274,500)	0
Net proceeds from Senior Notes	491,557	0
Repayment of Senior Notes	(350,000)	0
Proceeds from sale of Common Stock	3,157	2,490
Dividends paid	(3,373)	(3,353)
Other, net	(161)	(109)
Net cash provided by (used in) financing activities	97,180	(972)
Net change in cash and cash equivalents	(38)	(118,454)
Cash and cash equivalents at beginning of period	120	282,248
Cash and cash equivalents at ending of period	82	163,794
Supplemental schedule of additional cash flow information and noncash investing and financing activities:
Cash paid for interest, net of capitalized interest	64,899	47,403
Net cash paid for income taxes	$ 380	$ 162