Calculation of basic earnings per share and diluted earnings per share (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Calculation of basic earnings per share and diluted earnings per share
Net income	$ 919	$ 1,261
Weighted average common shares outstanding	6,836	6,835
Basic earnings per common share	$ 0	$ 0
Net income	$ 919	$ 1,261
Weighted average common shares outstanding	6,836	6,835
Dilutive effect of outstanding stock options	53	10
Average shares and dilutive potential common shares	6,889	6,845
Diluted earnings per common share	$ 0	$ 0
Shares of common stock not considered in computing diluted earnings per common share	204,890	214,302