Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Cash flows from operating activities
Net income	$ 50,245	$ 7,130
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation, depletion and amortization	75,386	70,854
Deferred income taxes	28,302	5,851
(Gain) loss from oil hedging activities	(24,309)	13,561
Non-hedge derivative (gains) losses	(62,065)	13,630
Loss on extinguishment of debt	21,696	20,576
(Gain) loss on sale of assets	48	(49)
Other	1,461	1,611
Change in assets and liabilities
Accounts receivable	(9,023)	(6,073)
Inventories	(6,144)	(24)
Prepaid expenses and other assets	2,676	2,255
Accounts payable and accrued liabilities	675	16,365
Revenue distribution payable	(3,728)	4,846
Stock-based compensation	1,076	1,597
Net cash provided by operating activities	76,296	152,130
Cash flows from investing activities
Purchase of property and equipment and oil and natural gas properties	(237,144)	(180,875)
Proceeds from dispositions of property and equipment and oil and natural gas properties	39,696	412
Settlement of non-hedge derivative instruments	13,604	(19,906)
Other	22	0
Net cash used in investing activities	(183,822)	(200,369)
Cash flows from financing activities
Proceeds from long-term debt	72,822	1,415
Repayment of long-term debt and capital lease obligations	(36,746)	(2,393)
Proceeds from Senior Notes	400,000	400,000
Repayment of Senior Notes	(325,000)	(325,000)
Payment of debt issuance costs and other financing fees	(8,867)	(11,577)
Payment of debt extinguishment costs	(15,809)	(15,085)
Net cash provided by financing activities	86,400	47,360
Net decrease in cash and cash equivalents	(21,126)	(879)
Cash and cash equivalents at beginning of period	34,589	55,111
Cash and cash equivalents at end of period	$ 13,463	$ 54,232