Repurchases Of Common Stock (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Repurchases Of Common Stock [Abstract]
Shares repurchased	2,197,000	801,000	3,746,000	3,139,000
Total cost of shares repurchased	$ 272,342,000	$ 76,575,000	$ 468,968,000	$ 282,910,000
Average cost per share	$ 123.98	$ 95.52	$ 125.18	$ 90.12
Shares acquired through employee surrenders			42,742	47,483
Cost of shares acquired through employee surrenders			$ 5,300,000	$ 4,300,000