Shareholders' Equity And Comprehensive Income (Schedule Of Treasury Shares Repurchased) (Details) (USD $)	12 Months Ended
	Dec. 31, 2011
Equity, Class of Treasury Stock [Line Items]
Total Number of Shares Purchased	900,000
Average Price Paid Per Share	$ 45.98
Total Number of Shares Purchased as Part of Publicly Announced Plan	900,000
Maximum Number of Shares Available for Purchase Pursuant to Publicity Announced Plan	900,000
Stock repurchase program, number of shares authorized	900,000
Stock repurchase program, additional number of shares authorized	900,000
August 1-31 [Member]
Equity, Class of Treasury Stock [Line Items]
Total Number of Shares Purchased	331,291
Average Price Paid Per Share	$ 46.03
Total Number of Shares Purchased as Part of Publicly Announced Plan	331,291
Maximum Number of Shares Available for Purchase Pursuant to Publicity Announced Plan	568,709
September 1-30 [Member]
Equity, Class of Treasury Stock [Line Items]
Total Number of Shares Purchased	568,709
Average Price Paid Per Share	$ 45.96
Total Number of Shares Purchased as Part of Publicly Announced Plan	568,709
October 1-31 [Member]
Equity, Class of Treasury Stock [Line Items]
Maximum Number of Shares Available for Purchase Pursuant to Publicity Announced Plan	900,000