CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Cash flows from operating activities:
Net income	$ 26,336	$ (18,503)
Adjustments to reconcile net income to net cash provided by operating activities:
Gain on divestiture activity	(1,462)	(24,915)
Depletion, depreciation, amortization, and asset retirement obligation liability accretion	169,570	105,356
Exploratory dry hole expense	606	40
Abandonment and impairment of unproved properties	142	3,079
Stock-based compensation expense	4,350	5,551
Change in Net Profits Plan liability	3,939	14,195
Unrealized derivative gain	7,652	82,012
Amortization of debt discount and deferred financing costs	3,665	3,620
Deferred income taxes	15,288	(18,174)
Other	(1,118)	(2,006)
Changes in current assets and liabilities:
Accounts receivable	(13,967)	16,385
Refundable income taxes	3,006	3,730
Prepaid expenses and other	(3,003)	20,959
Accounts payable and accrued expenses	(26,951)	(28,341)
Excess income tax benefit from the exercise of stock awards	0	(6,303)
Net cash provided by operating activities	188,053	156,685
Cash flows from investing activities:
Net proceeds from sale of oil and gas properties	1,679	39,023
Capital expenditures	(335,015)	(309,691)
Other	1,550	(2,355)
Net cash used in investing activities	(331,786)	(273,023)
Cash flows from financing activities:
Proceeds from credit facility	26,000	102,000
Repayment of credit facility	(2,000)	(150,000)
Net proceeds from 6.625% Senior Notes	0	341,435
Proceeds from sale of common stock	1,038	3,460
Excess income tax benefit from the exercise of stock awards	0	6,303
Other	(213)	(643)
Net cash provided by (used in) financing activities	24,825	302,555
Net change in cash and cash equivalents	(118,908)	186,217
Cash and cash equivalents at beginning of period	119,194	5,077
Cash and cash equivalents at end of period	286	191,294
Supplemental schedule of additional cash flow information and noncash investing and financing activities:
Cash paid for interest	(11,729)	(1,015)
Net cash refunded for income taxes	$ 3,397	$ 3,309