Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenues:
Oil and gas sales	$ 115,969	$ 225,021	$ 182,804
Expenses:
Lease operating expenses	40,130	48,597	43,743
Production taxes	2,470	5,927	3,950
Depreciation, depletion and amortization	63,497	87,818	71,445
Ceiling test write-down	266,562	0	0
General and administrative	20,777	22,870	26,512
Accretion of asset retirement obligation	3,259	2,958	1,753
Interest expense	33,766	29,281	21,886
Total expenses	430,461	197,451	169,289
Other income:
Gain on sale of assets	21,937	0	0
Other income	391	679	654
Derivative income	0	0	233
Other income (expense), net	22,328	679	887
Income (loss) from operations	(292,164)	28,249	14,402
Income tax expense (benefit)	2,626	(2,941)	320
Net income (loss)	(294,790)	31,190	14,082
Preferred stock dividend	5,139	5,139	5,139
Net income (loss) available to common stockholders	$ (299,929)	$ 26,051	$ 8,943
Basic
Net income (loss) per share (in usd per share)	$ (4.61)	$ 0.39	$ 0.14
Diluted
Net income (loss) per share (in usd per share)	$ (4.61)	$ 0.39	$ 0.14
Weighted average number of common shares:
Basic (shares)	65,022	64,204	63,054
Diluted (shares)	65,022	64,225	63,208