Net Income per Common Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Net income per common share
Net income	$ 9,351	$ 8,991	$ 5,296
Weighted-average shares outstanding used in computation of net income per share - basic	14,321,815	14,247,413	14,240,308
Dilutive effect of options, warrants and restricted stock	367,716	278,153	225,958
Shares used in computation of net income per common share - assuming dilution	14,689,531	14,525,566	14,466,266
Net income per common share - basic	$ 0.65	$ 0.63	$ 0.37
Net income per common share - diluted	$ 0.64	$ 0.62	$ 0.37