Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenues and other income
Oil, natural gas, and related product sales	$ 2,466,234	$ 2,409,867	$ 2,269,151
CO2 sales and transportation fees	27,950	26,453	22,711
Interest income and other income	22,943	20,152	17,462
Total revenues and other income	2,517,127	2,456,472	2,309,324
Expenses
Lease operating expenses	730,574	532,359	507,397
Marketing expenses	49,246	52,836	26,047
CO2 discovery and operating expenses	16,916	14,694	14,258
Taxes other than income	176,231	160,016	147,534
General and administrative expenses	145,211	144,019	125,525
Interest, net of amounts capitalized of $78,373, $77,432 and $61,586, respectively	140,709	153,581	164,360
Depletion, depreciation and amortization	509,943	507,538	409,196
Commodity derivatives expense (income)	41,024	(4,834)	(52,497)
Loss on early extinguishment of debt	44,651	0	16,131
Impairment of assets	0	17,515	22,951
Other expenses	20,242	21,891	4,377
Total expenses	1,874,747	1,599,615	1,385,279
Income before income taxes	642,380	856,857	924,045
Income tax provision	232,783	331,497	350,712
Net Income	$ 409,597	$ 525,360	$ 573,333
Net income per common share
Basic	$ 1.12	$ 1.36	$ 1.45
Diluted	$ 1.11	$ 1.35	$ 1.43
Weighted average common shares outstanding
Basic	366,659	385,205	396,023
Diluted	369,877	388,938	400,958