Net Income per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Net income per share
Net income	$ 2,266	$ 2,011	$ 9,351
Weighted average common shares outstanding	14,495,411	14,284,087
Dilutive effect of common stock options, warrants and restricted stock	291,169	316,688
Shares used in computation of net income per common share - diluted	14,786,580	14,600,775
Net income per common share - basic	$ 0.16	$ 0.14
Net income per common share - diluted	$ 0.15	$ 0.14