Stock Options (Detail Textuals 2) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options granted to purchase shares of common stock	21,000	23,500	23,404
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options granted to purchase shares of common stock	21,000	23,500	23,404
Weighted average fair value per option for options granted	11.03	8.98	3.89
Options exercisable	143,388	147,983	175,485
Weighted-average remaining contractual life of options	4 years 4 months 24 days	4 years 4 months 24 days	4 years 4 months 24 days
Unrecognized stock-based employee compensation expense	294,000
Unrecognized compensation cost weighted average recognition period	3 years 7 months 20 days