Stock-Based Compensation Plans (Stock Option Plan) (Details) (USD $)	1 Months Ended	12 Months Ended
	May 31, 2010	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Stock-Based Compensation Plans [Abstract]
Number of shares, options outstanding, beginning of year		121,000	127,000	81,000
Number of shares, granted	52,475	0	0	52,000
Number of shares, exercised		18,000	6,000	2,000
Number of shares, forfeited		8,000	0	4,000
Number of shares, expired		0	0	0
Number of shares, options outstanding, end of year		95,000	121,000	127,000
Number of shares, options exercisable		51,000	34,000	10,000
Weighted average exercise price per share, options outstanding, beginning of year		$ 22.81	$ 22.82	$ 23.30
Weighted average exercise price per share, granted		$ 0.00	$ 0.00	$ 22.07
Weighted average exercise price per share, exercised		$ 22.81	$ 22.93	$ 23.00
Weighted average exercise price per share, forfeited		$ 22.07	$ 0.00	$ 22.75
Weighted average exercise price per share, expired		$ 0.00	$ 0.00	$ 0.00
Weighted average exercise price per share, options outstanding, end of year		$ 22.87	$ 22.81	$ 22.82
Weighted average exercise price per share, options exercisable		$ 23.57	$ 24.01	$ 26.63