Market For Common Stock And Related Shareholder Matters (Price Ranges And Dividends Declared) (Details) (USD $)	3 Months Ended								12 Months Ended
	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2012 item
Number of common stock shareholders									13,800
Dividends Declared	$ 0.365	$ 0.365	$ 0.355	$ 0.355	$ 0.355	$ 0.355	$ 0.345	$ 0.345
Low [Member]
Price Range	$ 45.56	$ 41.57	$ 46.85	$ 44.51	$ 48.67	$ 66.39	$ 65.80	$ 51.66	45.56
High [Member]
Price Range	$ 54.99	$ 48.68	$ 56.97	$ 64.19	$ 75.98	$ 75.75	$ 74.00	$ 66.52	54.99