CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Operating Revenues
Oil and gas sales	$ 121,797	$ 103,371	$ 88,275
Operating Expenses
Lease operating expenses	33,072	30,637	28,845
Depreciation, depletion and amortization	47,172	30,517	21,993
General and administrative	19,844	14,819	15,358
Total operating expenses	100,088	75,973	66,196
Income from operations	21,709	27,398	22,079
Other income (expense)
Interest and other income	90	77	247
Interest expense	(3,311)	(3,188)	(3,500)
Gain (loss) on derivative financial instruments	(2,975)	(2,726)	1,528
Net other expense	(6,196)	(5,837)	(1,725)
Income before provision for income taxes	15,513	21,561	20,354
Deferred income tax benefit	(7)	(78)	(29)
Net income	15,520	21,639	20,383
Less dividends and accretion on preferred shares	10	10	18
Net income applicable to common stockholders	$ 15,510	$ 21,629	$ 20,365
Income per common share-Basic (in dollars per share)	$ 0.22	$ 0.31	$ 0.29
Income per common share-Diluted (in dollars per share)	$ 0.22	$ 0.30	$ 0.29
Weighted average common shares outstanding-Basic (in shares)	71,376,046	70,830,855	70,382,517
Weighted average common shares outstanding-Diluted (in shares)	72,096,672	72,047,488	71,429,110