Net Income Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Summary of net income per share
Net income	$ 3,681	$ 4,285	$ 7,466	$ 7,945
Weighted-average common shares outstanding	14,331	14,437	14,312	14,438
Basic earnings per share	$ 0.26	$ 0.30	$ 0.52	$ 0.55
Weighted-average common shares outstanding	14,331,252	14,436,606	14,312,348	14,438,363
Common stock equivalents due to effect of stock options	117	122	146	118
Total weighted-average common shares and equivalents	14,448	14,559	14,458	14,556
Diluted earnings per share	$ 0.25	$ 0.29	$ 0.52	$ 0.55