Stock Incentive Plan Summary of Stock Option Activity (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding, beginning of year	176,625	228,140	239,532	289,033
Outstanding Options, Weighted Average Exercise Price	$ 24.88	$ 23.09	$ 22.50	$ 20.54
Options, Outstanding, Weighted Average Remaining Contractual Term	2 years 296 days	3 years 117 days	4 years 58 days
Options, Outstanding, Intrinsic Value	$ 89,061	$ 159,552	$ 204,345
Granted	0	0	0
Options, Grants in Period, Weighted Average Exercise Price	$ 0	$ 0.00	$ 0.00
Exercised	44,763	11,392	49,500
Options, Exercises in Period, Weighted Average Exercise Price	$ 15.90	$ 10.67	$ 11.05
Forfeited or expired	(6,752)	0	(1)
Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price	$ 24.00	$ 0.00	$ 8.37
Options, Exercisable, Number	170,000	207,265	204,407
Options, Exercisable, Weighted Average Exercise Price	$ 24.95	$ 22.98	$ 22.18
Options, Exercisable, Weighted Average Remaining Contractual Term	2 years 252 days	2 years 361 days	3 years 212 days
Options, Exercisable, Intrinsic Value	89,061	159,552	204,345
Options, Exercises in Period, Total Intrinsic Value	$ 332,000	$ 90,000	$ 365,000
Antidilutive Outstanding and Exercisable option shares	108,125
Antidilutive Outstanding option shares		202,970	202,970
Antidilutive Exercisable option shares		182,095	167,845