Condensed Consolidated Statements of Operations (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Revenues and other income
Oil, natural gas, and related product sales	$ 573,653	$ 633,501
CO2 sales and transportation fees	6,558	6,795
Interest income and other income	2,875	4,820
Total revenues and other income	583,086	645,116
Expenses
Lease operating expenses	140,542	137,964
Marketing expenses	9,796	10,830
CO2 discovery and operating expenses	3,722	6,205
Taxes other than income	38,011	43,694
General and administrative	41,889	36,607
Interest, net of amounts capitalized of $21,705 and 19,445, respectively	36,034	36,314
Depletion, depreciation, and amortization	112,898	120,895
Derivatives expense (income)	11,929	45,275
Loss on early extinguishment of debt	44,223	0
Impairment of assets	0	17,300
Other expenses	2,107	10,720
Total expenses	441,151	465,804
Income before income taxes	141,935	179,312
Income Tax Provision	54,364	65,845
Net income	$ 87,571	$ 113,467
Net income per common share - basic	$ 0.24	$ 0.29
Net income per common share - diluted	$ 0.23	$ 0.29
Weighted average common shares outstanding
Basic	369,396	386,367
Diluted	372,867	390,943