CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenues:
Revenues	$ 556,274	$ 456,452	$ 1,123,408	$ 903,628
Costs and expenses:
Depreciation, depletion, and amortization	143,388	107,884	276,247	203,700
Asset retirement obligation	2,053	960	3,113	2,580
Production	79,215	62,578	150,486	124,999
Transportation, processing, and other operating	51,933	58,624	97,098	113,647
Gas gathering and other	9,467	8,647	19,290	17,074
Taxes other than income	27,930	17,477	58,118	38,790
General and administrative	19,739	19,762	43,060	37,796
Stock compensation	3,095	6,293	9,825	12,581
Loss (gain) on derivative instruments, net	21,699	(22,509)	17,540	(66,370)
Other operating expense, net	5,252	266	5,455	882
Total costs and expenses	363,771	259,982	680,232	485,679
Operating income	192,503	196,470	443,176	417,949
Other (income) and expense:
Interest expense	16,895	20,095	33,678	41,147
Capitalized interest	(4,850)	(5,442)	(9,660)	(12,083)
Loss on early extinguishment of debt	0	28,169	0	28,169
Other, net	(2,605)	(2,231)	(7,172)	(4,441)
Income before income tax	183,063	155,879	426,330	365,157
Income tax expense	42,066	58,617	99,015	136,923
Net income	$ 140,997	$ 97,262	$ 327,315	$ 228,234
Earnings per share to common stockholders:
Basic (USD per share)	$ 1.48	$ 1.02	$ 3.44	$ 2.40
Diluted (USD per share)	1.48	1.02	3.44	2.40
Dividends declared (USD per share)	$ 0.16	$ 0.08	$ 0.32	$ 0.16
Comprehensive income:
Net income	$ 140,997	$ 97,262	$ 327,315	$ 228,234
Other comprehensive income:
Change in fair value of investments, net of tax of $57, $128, $1, and $359, respectively	192	224	2	626
Total comprehensive income	141,189	97,486	327,317	228,860
Oil sales
Revenues:
Revenues	342,184	232,453	693,907	456,519
Gas and NGL sales
Revenues:
Revenues	202,202	213,360	405,920	425,731
Gas gathering and other
Revenues:
Revenues	11,810	10,735	23,262	21,360
Gas marketing
Revenues:
Revenues	$ 78	$ (96)	$ 319	$ 18