Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues and other income
Oil, natural gas, and related product sales	$ 935,751	$ 1,213,026	$ 2,372,473
CO2 sales and transportation fees	24,816	30,626	44,643
Interest income and other income	15,029	13,908	18,089
Total revenues and other income	975,596	1,257,560	2,435,205
Expenses
Lease operating expenses	414,937	515,043	647,559
Marketing and plant operating expenses	57,454	55,746	64,379
CO2 discovery and operating expenses	3,374	4,557	25,222
Taxes other than income	77,892	109,992	169,701
General and administrative expenses	109,926	144,564	158,343
Interest, net of amounts capitalized of $25,982, $32,146 and $24,202, respectively	125,145	159,268	183,003
Depletion, depreciation, and amortization	846,043	531,660	592,972
Commodity derivatives expense (income)	127,944	(147,999)	(555,255)
Loss (gain) on debt extinguishment	(115,095)	0	113,908
Write-down of oil and natural gas properties	810,921	4,939,600	0
Impairment of goodwill	0	1,261,512	0
Other expenses	37,402	9,599	12,816
Total expenses	2,495,943	7,583,542	1,412,648
Income (loss) before income taxes	(1,520,347)	(6,325,982)	1,022,557
Income tax provision (benefit)	(544,170)	(1,940,534)	387,066
Net income (loss)	$ (976,177)	$ (4,385,448)	$ 635,491
Net income (loss) per common share
Basic	$ (2.61)	$ (12.57)	$ 1.82
Diluted	(2.61)	(12.57)	1.81
Dividends declared per common share	$ 0	$ 0.1875	$ 0.25
Weighted average common shares outstanding
Basic	373,859	348,802	348,962
Diluted	373,859	348,802	351,167