Earnings Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Basic earnings per common share
Net income	$ (1,038)	$ 2,346	$ 8,972	$ (4,268)	$ 6,150	$ 3,967	$ 9,723	$ (800)	$ 6,012	$ 19,040	$ 1,662	$ 9,843
Less income allocated to participating securities									69	233	12
Net income attributable to common shareholders									5,943	18,807	1,650
Weighted average common shares outstanding									21,894,569	21,650,736	18,799,761
Basic earnings per common share (in dollars per share)	$ (0.05)	$ 0.11	$ 0.41	$ (0.19)	$ 0.28	$ 0.18	$ 0.44	$ (0.04)	$ 0.27	$ 0.87	$ 0.09
Earnings per common share assuming dilution
Net income	(1,038)	2,346	8,972	(4,268)	6,150	3,967	9,723	(800)	6,012	19,040	1,662	9,843
Less income allocated to participating securities									69	233	12
Net income attributable to common shareholders									$ 5,943	$ 18,807	$ 1,650
Weighted average common shares outstanding									21,894,569	21,650,736	18,799,761
Incremental shares applicable to stock based compensation									69,742	163,881	487,685
Weighted average common shares assuming dilution									21,964,311	21,814,617	19,287,446
Earnings per common share assuming dilution (in dollars per share)	$ (0.05)	$ 0.10	$ 0.40	$ (0.19)	$ 0.28	$ 0.18	$ 0.44	$ (0.04)	$ 0.26	$ 0.85	$ 0.09