Stock Based Compensation Plan (Details) (USD $)	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding, Beginning of Period, in shares	482,765
Granted, in shares	75,786
Stock Options Exercised, in shares	(67,831)	(40,986)
Forfeited, in shares	(18,362)
Outstanding, End of Period, in shares	472,358
Exercisable at Period End, in shares	289,123
Vested and Expected to Vest, in shares	472,358
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Outstanding at Beginning of Period, in dollars per share	$ 22.46
Granted, in dollars per share	$ 24.92
Excercised, in dollars per share	$ 21.40
Forfeited, in dollars per share	$ 23.93
Outstanding, End of Period, in dollars per share	$ 22.95
Exercisable at Period End, in dollars per share	$ 22.39
Vested and Expected to Vest, in dollars per share	$ 22.95
Fair Value, in dollars per share	$ 6.01
Dividend Yield	3.93%
Expected Volatility	37.43%
Risk Free Interest Rate	1.22%
Expected Lives, in years	6 years 5 months 16 days