CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (UNAUDITED) (in thousands, except per share data) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Operating revenues and other income:
Oil, gas, and NGL production revenue	$ 402,558	$ 284,939	$ 785,444	$ 618,137
Net gain (loss) on divestiture activity	39,501	(167,133)	424,870	(129,670)
Other operating revenues	1,857	2,915	3,197	4,992
Total operating revenues and other income	443,916	120,721	1,213,511	493,459
Operating expenses:
Oil, gas, and NGL production expense	117,400	124,376	238,279	262,422
Depletion, depreciation, amortization, and asset retirement obligation liability accretion	151,765	153,232	282,238	291,044
Exploration	14,056	12,983	27,783	24,800
Abandonment and impairment of unproved properties	11,935	157	17,560	157
General and administrative	28,920	28,237	56,602	57,054
Net derivative (gain) loss	63,749	(55,189)	71,278	(169,963)
Other operating expenses, net	(57)	4,251	4,555	9,110
Total operating expenses	387,768	268,047	698,295	474,624
Income (loss) from operations	56,148	(147,326)	515,216	18,835
Interest expense	(41,654)	(44,595)	(84,739)	(91,548)
Loss on extinguishment of debt	0	0	0	(35)
Other non-operating income, net	1,802	953	2,211	720
Income (loss) before income taxes	16,296	(190,968)	432,688	(72,028)
Income tax (expense) benefit	901	71,061	(98,090)	26,555
Net income (loss)	$ 17,197	$ (119,907)	$ 334,598	$ (45,473)
Basic weighted-average common shares outstanding	111,701	111,277	111,698	111,274
Diluted weighted-average common shares outstanding	113,630	111,277	113,267	111,274
Basic net income (loss) per common share	$ 0.15	$ (1.08)	$ 3.00	$ (0.41)
Diluted net income (loss) per common share	0.15	(1.08)	2.95	(0.41)
Dividends per common share	$ 0.00	$ 0.00	$ 0.05	$ 0.05