Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Revenues and other income
Oil, natural gas, and related product sales	$ 187,803	$ 297,470
CO2 sales and transportation fees	6,272	6,972
Interest income and other income	769	3,207
Total revenues and other income	194,844	307,649
Expenses
Lease operating expenses	102,447	141,084
Marketing and plant operating expenses	13,194	11,685
CO2 discovery and operating expenses	607	947
Taxes other than income	20,092	26,679
General and administrative expenses	33,901	46,280
Interest, net of amounts capitalized of $5,780 and $8,409, respectively	42,171	40,099
Depletion, depreciation, and amortization	77,366	149,958
Commodity derivatives expense (income)	22,826	(83,076)
Gain on debt extinguishment	(94,991)	0
Write-down of oil and natural gas properties	256,000	146,200
Other expenses	1,544	0
Total expenses	475,157	479,856
Loss before income taxes	(280,313)	(172,207)
Income tax benefit	(95,120)	(64,461)
Net loss	$ (185,193)	$ (107,746)
Net loss per common share
Basic	$ (0.53)	$ (0.31)
Diluted	(0.53)	(0.31)
Dividends declared per common share	$ 0	$ 0.0625
Weighted average common shares outstanding
Basic	347,235	350,688
Diluted	347,235	350,688