Stock Based Compensation Plan (Details) (USD $)	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding, Beginning of Period, in shares	473,435
Granted, in shares	74,300
Stock Options Exercised, in shares	(52,502)	(14,717)
Forfeited, in shares	(8,354)
Outstanding, End of Period, in shares	486,879
Exercisable at Period End, in shares	300,532
Vested and Expected to Vest, in shares	486,879
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	$ 22.91
Granted, in dollars per share	$ 25.42
Excercised, in dollars per share	$ 21.89
Forfeited, in dollars per share	$ 24.43
Outstanding, End of Period, in dollars per share	$ 23.38
Exercisable at Period End, in dollars per share	$ 22.80
Vested and Expected to Vest, in dollars per share	$ 23.38
Fair Value, in dollars per share	$ 6.13
Dividend Yield	3.93%
Expected Volatility	37.43%
Risk Free Interest Rate	1.22%
Expected Lives, in years	6 years 5 months 16 days