CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (UNAUDITED) (in thousands, except per share amounts) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Operating revenues:
Oil, gas, and NGL production revenue	$ 291,142	$ 441,256	$ 502,965	$ 834,571
Net gain (loss) on divestiture activity (note 3)	50,046	71,884	(18,975)	36,082
Other operating revenues	626	3,006	900	11,427
Total operating revenues and other income	341,814	516,146	484,890	882,080
Operating expenses:
Oil, gas, and NGL production expense	148,591	173,685	293,134	369,836
Depletion, depreciation, amortization, and asset retirement obligation liability accretion	211,020	219,704	425,227	437,105
Exploration	13,187	25,541	28,460	62,948
Impairment of proved properties	0	12,914	269,785	68,440
Abandonment and impairment of unproved properties	38	5,819	2,349	17,446
General and administrative	28,200	42,605	60,438	86,244
Change in Net Profits Plan liability	3,125	(4,476)	1,865	(8,810)
Derivative (gain) loss	163,351	80,929	149,123	(73,238)
Other operating expenses	4,851	10,304	11,783	27,423
Total operating expenses	572,363	567,025	1,242,164	987,394
Loss from operations	(230,549)	(50,879)	(757,274)	(105,314)
Non-operating income (expense):
Interest income	5	25	11	596
Interest expense	(34,035)	(30,779)	(65,123)	(63,426)
Gain (loss) on extinguishment of debt	0	(16,578)	15,722	(16,578)
Loss before income taxes	(264,579)	(98,211)	(806,664)	(184,722)
Income tax benefit	95,898	40,703	290,773	74,156
Net loss	$ (168,681)	$ (57,508)	$ (515,891)	$ (110,566)
Basic weighted-average common shares outstanding	68,102	67,483	68,090	67,473
Diluted weighted-average common shares outstanding	68,102	67,483	68,090	67,473
Basic net loss per common share	$ (2.48)	$ (0.85)	$ (7.58)	$ (1.64)
Diluted net loss per common share	(2.48)	(0.85)	(7.58)	(1.64)
Dividends per common share	$ 0.00	$ 0.00	$ 0.05	$ 0.05