Stock-Based Compensation Plans (Schedule of Stock Option Activity) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012
Number of Shares
Options outstanding at January 1, 2012	157,000
Granted	9,500
Exercised	(18,450)
Forfeited and expired	(8,650)
Options outstanding at December 31, 2012	139,400
Options exercisable at December 31, 2012	79,900
Weighted Average Exercise Price Per Share
Options outstanding at January 1, 2012	$ 32.36
Granted	$ 34.99
Exercised	$ 27.97
Forfeited and expired	$ 34.8
Options outstanding at December 31, 2012	$ 32.97
Options exercisable at December 31, 2012	$ 34.47
Weighted- Average Remaining Contractual Term
Options outstanding at December 31, 2012	5 years 9 months 18 days
Options exercisable at December 31, 2012	4 years 7 months 6 days
Aggregate Intrinsic Value
Options outstanding at December 31, 2012	$ 369
Options exercisable at December 31, 2012	$ 178