CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Revenues
Crude oil	$ 420,286		$ 347,407		$ 229,572
Natural gas liquids (NGLs)	34,552		30,748		31,051
Natural gas	58,044		52,538		49,861
Gain (loss) on sales of property and equipment, net	120,769		(266)		4,282
Other	3,122		1,041		2,383
Total revenues	636,773		431,468		317,149
Operating expenses
Lease operating	48,298		35,461		31,266
Gathering, processing and transportation	18,294		12,839		14,196
Production and ad valorem taxes	27,990		22,404		10,634
General and administrative	49,005		53,998		45,900
Exploration	17,063		20,994		34,092
Depreciation, depletion and amortization	300,299		245,594		206,336
Impairments	791,809		132,224		104,484
Loss on firm transportation commitment	0		0		17,332
Total operating expenses	1,252,758		523,514		464,240
Operating loss	(615,985)		(92,046)		(147,091)
Other income (expense)
Interest expense	(88,831)		(78,841)		(59,339)
Loss on extinguishment of debt	0		(29,174)		(3,164)
Derivatives	162,212		(20,852)		36,187
Other	1,334		147		116
Loss before income taxes	(541,270)		(220,766)		(173,291)
Income tax benefit	131,678		77,696		68,702
Net loss	(409,592)		(143,070)		(104,589)
Preferred stock dividends	(17,148)	[1]	(6,900)	[1]	(1,687)	[1]
Induced conversion of preferred stock	(4,256)		0		0
Net loss attributable to common shareholders	$ (430,996)		$ (149,970)		$ (106,276)
Net loss per share:
Basic (in dollars per share)	$ (6.26)		$ (2.41)		$ (2.22)
Diluted (in dollars per share)	$ (6.26)		$ (2.41)		$ (2.22)
Weighted average shares outstanding – basic	68,887		62,335		47,919
Weighted average shares outstanding – diluted	68,887		62,335		47,919

[1] Preferred stock dividends were excluded from diluted earnings per share for the years ended December 31, 2014, 2013 and 2012, as the assumed conversion of the outstanding preferred stock would have been anti-dilutive.