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:
Oil and gas sales	$ 225,021	$ 182,804	$ 141,433
Expenses:
Lease operating expenses	48,597	43,743	38,890
Production taxes	5,927	3,950	885
Depreciation, depletion and amortization	87,818	71,445	60,689
Ceiling test write-down	0	0	137,100
General and administrative	22,870	26,512	22,957
Accretion of asset retirement obligation	2,958	1,753	2,078
Interest expense	29,281	21,886	9,808
Total expenses	197,451	169,289	272,407
Other income (expense):
Other income	679	654	764
Derivative income (expense)	0	233	(233)
Other income (expense), net	679	887	531
Income (loss) from operations	28,249	14,402	(130,443)
Income tax expense (benefit)	(2,941)	320	1,636
Net income (loss)	31,190	14,082	(132,079)
Preferred stock dividend	5,139	5,139	5,139
Net income (loss) available to common stockholders	$ 26,051	$ 8,943	$ (137,218)
Basic
Net income (loss) per share (in usd per share)	$ 0.39	$ 0.14	$ (2.20)
Diluted
Net income (loss) per share (in usd per share)	$ 0.39	$ 0.14	$ (2.20)
Weighted average number of common shares:
Basic (shares)	64,204	63,054	62,459
Diluted (shares)	64,225	63,208	62,459