Stock Option Plans - Stock Option Activity (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Options outstanding at the beginning of the year	943,000	838,950
Options granted	215,438	185,500
Options forfeited	(6,250)	(2,000)
Options exercised	(33,500)	(79,450)
Options outstanding at the end of the year	1,118,688	943,000
Options exercisable at the end of the year	672,125	554,500
Common stock available for future grants at the end of the year	61,500	107,438
Granted	$ 10.47	$ 9.67
Forfeited	$ 6.98	$ 10.10
Exercised	$ 5.13	$ 3.31
Outstanding	$ 10.96	$ 10.84
Exercisable	$ 11.65	$ 11.69