Stock-Based Compensation Stock-Based Compensation (Activity Pertaining to Stock Options) (Details) (USD $)	0 Months Ended	12 Months Ended
	May 05, 2010	Dec. 31, 2012 Stock Options [Member]	Dec. 31, 2011 Stock Options [Member]	Dec. 31, 2010 Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares, Beginning Balance		138,980	184,765	219,625
Weighted Average Grant Date Price, Beginning Balance		$ 31.39	$ 31.11	$ 29.61
Number of Shares, Granted	24,504	0	0	0
Weighted Average Grant Date Price, Granted		$ 0.00	$ 0.00	$ 0.00
Number of Shares, Exercised		(18,850)	(42,285)	(32,360)
Weighted Average Grant Date Price, Exercised		$ 20.38	$ 28.29	$ 20.35
Number of Shares, Forfeited		(2,100)	(3,500)	(2,500)
Weighted Average Grant Date Price, Forfeited		$ 37.83	$ 53.90	$ 37.83
Number of Shares, Ending Balance		118,030	138,980	184,765
Weighted Average Grant Date Price, Ending Balance		$ 33.03	$ 31.39	$ 31.11