Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues and other income	$ 1,274,883	$ 1,473,625	$ 1,129,786
Expenses
Taxes other than income	93,752	104,670	87,207
General and administrative expenses	83,029	71,495	101,806
Interest, net of amounts capitalized of $36,671, $37,079 and $30,762, respectively	81,632	69,688	99,263
Depletion, depreciation, and amortization	233,816	216,449	207,713
Commodity derivatives expense (income)	70,078	(21,087)	77,576
Gain on debt extinguishment	(155,998)	0	0
Other expenses	11,187	84,325	11,455
Total expenses	953,572	1,063,694	1,083,286
Income before income taxes	321,311	409,931	46,500
Income tax provision (benefit)	104,352	87,233	(116,652)
Net income	$ 216,959	$ 322,698	$ 163,152
Net income per common share
Basic	$ 0.47	$ 0.75	$ 0.42
Diluted	$ 0.45	$ 0.71	$ 0.41
Weighted average common shares outstanding
Basic	459,524	432,483	390,928
Diluted	510,341	456,169	395,921
Other income
Revenues and other income	$ 14,523	$ 17,970	$ 10,220
Transportation and marketing
Operating expenses	41,810	43,942	44,064
Oil, natural gas, and related product sales
Revenues and other income	1,212,020	1,422,589	1,089,666
Operating expenses	477,220	489,720	447,799
CO2
Revenues and other income	34,142	31,145	26,182
Operating expenses	2,922	2,816	3,099
Purchased oil sales
Revenues and other income	14,198	1,921	3,718
Operating expenses	$ 14,124	$ 1,676	$ 3,304