Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Cash flows from operating activities
Net income (loss)	$ 42,048	$ 33,713	$ (144,318)
Adjustments to reconcile net income (loss) to net cash provided by operating activities
Depreciation, depletion and amortization	146,083	109,503	104,193
Depreciation, depletion, & amortization of discontinued operations	0	0	541
Loss on impairment of oil and natural gas properties	0	0	240,790
Loss on impairment of other assets	0	4,150	0
Litigation settlement	0	0	2,928
Deferred income taxes	35,745	23,724	(85,913)
Unrealized (gain) loss on ineffective portion of hedges and reclassification adjustments	27,452	23,889	(21,752)
Non-hedge derivative gains	(34,408)	(38,595)	(11,169)
Loss on extinguishment of debt	20,592	2,241	0
Net gain on sale of assets	(1,284)	(184)	(10,463)
Other	3,057	2,211	2,141
Change in assets and liabilities
Accounts receivable	(4,762)	(6,463)	17,648
Inventories	328	(785)	6,048
Prepaid expenses and other assets	1,583	5,141	12,084
Accounts payable and accrued liabilities	16,519	9,452	(13,265)
Revenue distribution payable	3,577	(1,450)	(1,154)
Stock-based compensation	3,086	1,155	336
Net cash provided by operating activities	259,616	167,702	98,675
Cash flows from investing activities
Purchase of property and equipment and oil and natural gas properties	(339,863)	(310,125)	(178,154)
Proceeds from asset dispositions	38,356	445	25,861
Return of prepaid production tax asset	0	0	13,544
Settlement of non-hedge derivative instruments	(23,491)	45,490	160,275
Other	0	18	378
Net cash provided by (used in) investing activities	(324,998)	(264,172)	21,904
Cash flows from financing activities
Proceeds from long-term debt	21,724	209,533	158
Repayment of long-term debt	(24,785)	(717,561)	(94,795)
Proceeds from Senior Notes	400,000	293,016	0
Repayment of Senior Notes	(325,000)	0	0
Proceeds from equity issuance	0	313,231	0
Principal payments under capital lease obligations	(120)	(249)	(258)
Payment of debt issuance costs and other financing fees	(11,858)	(19,806)	(4,379)
Payment of debt extinguishment costs	(15,101)	0	0
Net cash provided by (used in) financing activities	44,860	78,164	(99,274)
Net increase (decrease) in cash and cash equivalents	(20,522)	(18,306)	21,305
Cash and cash equivalents at beginning of period	55,111	73,417	52,112
Cash and cash equivalents at end of period	$ 34,589	$ 55,111	$ 73,417