CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (UNAUDITED) (in thousands, except per share data) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Operating revenues and other income:
Oil, gas, and NGL production revenue	$ 458,382	$ 294,459	$ 1,243,826	$ 912,596
Net gain (loss) on divestiture activity	786	(1,895)	425,656	(131,565)
Other operating revenues	201	2,815	3,398	7,807
Total operating revenues and other income	459,369	295,379	1,672,880	788,838
Operating expenses:
Oil, gas, and NGL production expense	127,638	122,651	365,917	385,073
Depletion, depreciation, amortization, and asset retirement obligation liability accretion	201,105	134,599	483,343	425,643
Exploration	13,061	14,119	40,844	38,919
Abandonment and impairment of unproved properties	9,055	0	26,615	157
General and administrative	29,464	27,564	86,066	84,618
Net derivative (gain) loss	178,026	80,599	249,304	(89,364)
Other operating expenses, net	9,664	999	14,219	10,109
Total operating expenses	568,013	380,531	1,266,308	855,155
Income (loss) from operations	(108,644)	(85,152)	406,572	(66,317)
Interest expense	(38,111)	(44,091)	(122,850)	(135,639)
Loss on extinguishment of debt	(26,722)	0	(26,722)	(35)
Other non-operating income, net	806	861	3,017	1,581
Income (loss) before income taxes	(172,671)	(128,382)	260,017	(200,410)
Income tax (expense) benefit	36,748	39,270	(61,342)	65,825
Net income (loss)	$ (135,923)	$ (89,112)	$ 198,675	$ (134,585)
Basic weighted-average common shares outstanding	112,107	111,575	111,836	111,366
Diluted weighted-average common shares outstanding	112,107	111,575	113,600	111,366
Basic net income (loss) per common share	$ (1.21)	$ (0.80)	$ 1.78	$ (1.21)
Diluted net income (loss) per common share	(1.21)	(0.80)	1.75	(1.21)
Dividends per common share	$ 0.05	$ 0.05	$ 0.10	$ 0.10