CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2014		Jun. 30, 2013
Statement of Cash Flows [Abstract]
Net income	$ 125,387		$ 93,249
Adjustments to reconcile net income to net cash provided by operating activities:
Gain on divestiture activity	5,484		5,706
Depletion, depreciation, amortization, and asset retirement obligation liability accretion	364,996		424,440
Exploratory dry hole expense	6,459		5,886
Impairment of proved properties	0		55,771
Abandonment and impairment of unproved properties	2,965		4,641
Stock-based compensation expense	14,341		18,068
Change in Net Profits Plan liability	(8,881)		(7,363)
Derivative loss (gain)	224,131	[1]	(54,618)	[1]
Derivative cash settlement (loss) gain	(62,620)	[2]	14,003	[2]
Amortization of deferred financing costs	2,954		2,440
Deferred income taxes	73,911		56,239
Plugging and abandonment	(3,219)		(3,746)
Other, net	(4,827)		5,769
Changes in current assets and liabilities:
Accounts receivable	(2,558)		(59,284)
Prepaid expenses and other	1,302		(32)
Accounts payable and accrued expenses	(13,704)		46,598
Net Cash Provided by Operating Activities	715,153		596,355
Cash flows from investing activities:
Net proceeds from sale of oil and gas properties	46,821		20,343
Capital expenditures	(778,580)		(733,992)
Acquisition of proved and unproved oil and gas properties	(98,619)		(59,201)
Other, net	(2,257)		(4,940)
Net Cash Provided by (Used in) Investing Activities	(832,635)		(777,790)
Cash flows from financing activities:
Proceeds from credit facility	0		516,500
Repayment of credit facility	0		(828,500)
Deferred financing costs related to credit facility	0		(3,444)
Net proceeds from 2024 notes	0		490,820
Proceeds from sale of common stock	2,490		3,652
Dividends paid	(3,353)		(3,314)
Other, net	(109)		(29)
Net cash provided by (used in) financing activities	(972)		175,685
Net change in cash and cash equivalents	(118,454)		(5,750)
Cash and cash equivalents at beginning of period	282,248		5,926
Cash and cash equivalents at ending of period	163,794		176
Supplemental schedule of additional cash flow information and noncash investing and financing activities:
Cash paid for interest, net of capitalized interest	47,403		36,089
Net cash paid (refunded) for income taxes	162		(332)
Assets Held for Sale
Document Period End Date	Jun. 30, 2014
Assets Held-for-sale Reasonably Certain Period for Sale	1
Oil and gas properties held for sale net of accumulated depletion, depreciation and amortization of $23,697 and $7,390, respectively	23,935
Asset retirement obligation associated with oil and gas properties held for sale	$ 2,760

[1] (2) Total derivative loss (gain) is reported in the derivative loss (gain) line item on the condensed consolidated statements of cash flows within cash provided by operating activities.

[2] (1) Total derivative cash settlement loss (gain) is reported in the derivative cash settlement (loss) gain line item on the condensed consolidated statements of cash flows within net cash provided by operating activities.