Shareholders' Equity And Comprehensive Income (Schedule Of Treasury Shares Repurchased) (Detail) (USD $)	6 Months Ended
	Jun. 30, 2012
Total Number of Shares Purchased	48,188
Average Price Paid Per Share	$ 47.93
Total Number of Shares Purchased as Part of Publicly Announced Plan	48,188
Maximum Number of Shares Available for Purchase Pursuant to Publicly Announced Plan	851,812
June 1-30 [Member]
Total Number of Shares Purchased	48,188
Average Price Paid Per Share	$ 47.93
Total Number of Shares Purchased as Part of Publicly Announced Plan	48,188
Maximum Number of Shares Available for Purchase Pursuant to Publicly Announced Plan	851,812