Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenues	$ 394,973	$ 266,559	$ 1,135,270	$ 803,197
Expenses
CO2 discovery and operating expenses	708	1,346	1,670	2,452
Taxes other than income	27,344	20,233	81,897	62,848
General and administrative expenses	21,579	27,273	61,223	81,303
Interest, net of amounts capitalized of $9,514, $9,416, $26,817 and $22,217, respectively	18,527	24,546	51,974	75,785
Depletion, depreciation, and amortization	51,316	52,101	156,711	154,448
Commodity derivatives expense (income)	44,577	25,263	189,601	(9,712)
Other expenses	1,933	0	7,241	0
Total expenses	300,938	280,346	947,984	749,808
Income (loss) before income taxes	94,035	(13,787)	187,286	53,389
Income tax provision (benefit)	15,616	(14,229)	39,067	17,018
Net income	$ 78,419	$ 442	$ 148,219	$ 36,371
Net income per common share
Basic	$ 0.17	$ 0.00	$ 0.35	$ 0.09
Diluted	$ 0.17	$ 0.00	$ 0.33	$ 0.09
Weighted average common shares outstanding
Basic	451,256	392,013	426,036	390,448
Diluted	458,450	393,023	455,934	392,625
Other income
Revenues	$ 7,196	$ 939	$ 17,640	$ 8,576
Lease operating expenses
Operating expenses	122,527	117,768	361,267	342,926
Marketing and plant operating expenses
Operating expenses	12,427	11,816	36,400	39,758
Oil, natural gas, and related product sales
Revenues	379,628	259,030	1,095,214	776,088
CO2 sales and transportation fees
Revenues	$ 8,149	$ 6,590	$ 22,416	$ 18,533