Shareholders' Equity (Schedule Of Share Repurchases) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Share repurchases:
Shares repurchased, shares	3,655,959	1,419,163
Cost of shares repurchased	$ 263,942	$ 86,700	$ 674,662
Shares repurchased, average price per share	$ 72.20	$ 61.09
Repurchase authorization approved	500,000
Excluding Privately Negotiated Transactions [Member]
Share repurchases:
Shares repurchased, shares			4,651,279
Cost of shares repurchased			$ 239,127
Shares repurchased, average price per share			$ 51.41