Condensed Consolidated Statement of Cash Flows (Unaudited) (USD $) In Thousands	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010
Cash flows from operating activities:
Net income	$ 148,809	$ 72,672
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion and amortization	204,777	184,900
Accretion expense	23,134	25,384
Deferred income tax provision	97,926	36,711
Settlement of asset retirement obligations	(52,543)	(28,652)
Non-cash stock compensation expense	4,492	4,023
Excess tax benefits	(1,490)	(297)
Non-cash derivative income	(4,337)	(1,459)
Loss on early extinguishment of debt	607	1,820
Other non-cash expense	50	741
Change in current income taxes	(21,710)	(6,014)
(Increase) decrease in accounts receivable	(17,117)	39,569
Increase in other current assets	(185)	(305)
Decrease in inventory	1,606	1,778
Increase (decrease) in accounts payable	2,679	(1,265)
Increase (decrease) in other current liabilities	3,604	(21,401)
Other	(1,889)	1,261
Net cash provided by operating activities	388,413	309,466
Cash flows from investing activities:
Investment in oil and gas properties	(430,711)	(261,970)
Proceeds from sale of oil and gas properties, net of expenses	7,692	31,635
Investment in fixed and other assets	(1,788)	(1,722)
Net cash used in investing activities	(424,807)	(232,057)
Cash flows from financing activities:
Repayments of bank borrowings		(125,000)
Redemption of senior subordinated notes		(200,503)
Proceeds from issuance of senior notes		275,000
Deferred financing costs	(4,017)	(9,766)
Excess tax benefits	1,490	297
Net payments for share based compensation	(2,581)	(1,360)
Net cash used in financing activities	(5,108)	(61,332)
Net increase (decrease) in cash and cash equivalents	(41,502)	16,077
Cash and cash equivalents, beginning of period	106,956	69,293
Cash and cash equivalents, end of period	$ 65,454	$ 85,370