Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
Cash flows from operating activities
Net income	$ 45,299	$ 71,726
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation, depletion and amortization	119,807	107,913
Deferred income taxes	25,540	44,841
(Gain) loss from oil hedging activities	(35,777)	20,450
Non-hedge derivative gains	(37,035)	(79,971)
Loss on extinguishment of debt	21,714	20,576
Loss on sale of assets	21	138
Other	2,167	2,395
Change in assets and liabilities
Accounts receivable	(13,140)	(1,357)
Inventories	(4,599)	341
Prepaid expenses and other assets	1,763	1,723
Accounts payable and accrued liabilities	13,355	1,133
Revenue distribution payable	(2,215)	3,189
Stock-based compensation	2,077	2,011
Net cash provided by operating activities	138,977	195,108
Cash flows from investing activities
Purchase of property and equipment and oil and natural gas properties	(379,069)	(258,530)
Proceeds from dispositions of property and equipment and oil and natural gas properties	45,023	351
Settlement of non-hedge derivative instruments	24,309	(21,610)
Other	23	0
Net cash used in investing activities	(309,714)	(279,789)
Cash flows from financing activities
Proceeds from long-term debt	156,457	21,641
Repayment of long-term debt and capital lease obligations	(37,618)	(3,671)
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)	(11,638)
Payment of debt extinguishment costs	(15,827)	(15,085)
Net cash provided by financing activities	169,145	66,247
Net decrease in cash and cash equivalents	(1,592)	(18,434)
Cash and cash equivalents at beginning of period	34,589	55,111
Cash and cash equivalents at end of period	$ 32,997	$ 36,677