Shareholders' Equity (Schedule Of Share Repurchases) (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Share repurchases:
Shares repurchased, shares	508,328	905,383	940,445	2,336,187
Cost of shares repurchased	$ 46,326,000	$ 66,435,000	$ 82,571,000	$ 159,458,000
Shares repurchased, average price per share	$ 91.13	$ 73.38	$ 87.80	$ 68.26
Repurchase authorization approved			$ 500,000,000