Stock-Based Compensation (Activity Pertaining To SAR, Stock Option Plan And Directors Plan) (Details) (USD $)	0 Months Ended	12 Months Ended									12 Months Ended
	May 05, 2010	Dec. 31, 2011	Dec. 31, 2009	Dec. 31, 2011 Stock Options Plan [Member]	Dec. 31, 2010 Stock Options Plan [Member]	Dec. 31, 2009 Stock Options Plan [Member]	Dec. 31, 2011 Restricted Stock [Member]	Dec. 31, 2010 Restricted Stock [Member]	Dec. 31, 2009 Restricted Stock [Member]	Dec. 31, 2008 Restricted Stock [Member]	Dec. 31, 2011 Stock Appreciation Rights (SARs) [Member]	Dec. 31, 2010 Stock Appreciation Rights (SARs) [Member]	Dec. 31, 2009 Stock Appreciation Rights (SARs) [Member]	Dec. 31, 2011 Directors Plan [Member]	Dec. 31, 2010 Directors Plan [Member]	Dec. 31, 2009 Directors Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares, Beginning Balance				184,765	219,625	228,290					145,901	145,901	145,901	178,500	143,496	153,000
Weighted Average Grant Date Price, Beginning Balance				$ 31.11	$ 29.61	$ 29.68	$ 47.44	$ 47.39	$ 47.46	$ 47.40	$ 46.59	$ 46.59	$ 46.59	$ 48.77	$ 49.38	$ 46.85
Number of shares, granted	24,504	3,500	437	0	0	0					0	0	0	31,500	52,504	3,496
Weighted Average Grant Date Price, Granted				$ 0.00	$ 0.00	$ 0.00	$ 55.91	$ 41.09	$ 0.00		$ 0.00	$ 0.00	$ 0.00	$ 53.81	$ 37.62	$ 31.30
Number of Shares, Exercised				(42,285)	(32,360)	(4,065)					0	0	0	(10,500)	(3,500)	(13,000)
Weighted Average Grant Date Price, Exercised				$ 28.29	$ 20.35	$ 23.45					$ 0.00	$ 0.00	$ 0.00	$ 21.96	$ 17.54	$ 14.74
Number of Shares, Forfeited				(3,500)	(2,500)	(4,600)					0	0	0	0	(14,000)
Weighted Average Grant Date Price, Forfeited				$ 53.90	$ 37.83	$ 38.60					$ 0.00	$ 0.00	$ 0.00	$ 0.00	$ 58.20
Number of Shares, Ending Balance				138,980	184,765	219,625					145,901	145,901	145,901	199,500	178,500	143,496
Weighted Average Grant Date Price, Ending Balance				$ 31.39	$ 31.11	$ 29.61	$ 47.44	$ 47.39	$ 47.46	$ 47.40	$ 46.59	$ 46.59	$ 46.59	$ 48.37	$ 48.77	$ 49.38