Consolidated Statements of Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Revenues
Oil, natural gas liquids and natural gas sales	$ 163,973	$ 188,398	$ 458,374	$ 595,510
Gain (loss) on derivative instruments, net	20,412	107,173	(40,005)	90,245
Total revenues	184,385	295,571	418,369	685,755
Operating Costs and Expenses
Oil, natural gas liquids and natural gas production	42,280	54,598	132,847	175,933
Production and ad valorem taxes	10,987	13,366	33,422	45,783
Depreciation, depletion and amortization	108,167	149,781	344,564	434,005
Asset impairment	587	399,394	220,612	466,390
Exploration	18	493	1,780	12,274
General and administrative (including non-cash stock based compensation of $6,518 and $933 for the three months ended September 30, 2016 and 2015, respectively, and $14,493 and $12,040 for the nine months ended September 30, 2016 and 2015, respectively)	21,710	23,631	74,783	94,338
Accretion of discount on asset retirement obligations	1,556	1,700	5,092	5,379
(Gain) loss on sale of assets and other	(91,222)	822	(252,097)	(26,046)
Total operating costs and expenses	94,083	643,785	561,003	1,208,056
Operating Income (Loss)	90,302	(348,214)	(142,634)	(522,301)
Other Income (Expense)
Interest expense	(8,987)	(10,084)	(27,858)	(33,086)
Other income	421	56	580	143
Total other expense	(8,566)	(10,028)	(27,278)	(32,943)
Income (Loss) Before Income Taxes	81,736	(358,242)	(169,912)	(555,244)
Income tax expense (benefit)	28,422	(130,338)	(56,869)	(200,319)
Net Income (Loss)	$ 53,314	$ (227,904)	$ (113,043)	$ (354,925)
Diluted Earnings Per Average Common Share (in dollars per share)	$ 0.55	$ (2.89)	$ (1.21)	$ (4.72)
Basic Earnings Per Average Common Share (in dollars per share)	$ 0.55	$ (2.89)	$ (1.21)	$ (4.72)
Diluted Average Common Shares Outstanding (in shares)	97,511	78,742	93,602	75,125
Basic Average Common Shares Outstanding (in shares)	97,068	78,742	93,602	75,125
Dividends Per Common Share (in dollars per share)	$ 0	$ 0.02	$ 0	$ 0.06