Stock Option Plans (Stock Option Activity) (Details) (USD $)	12 Months Ended
	Jul. 31, 2012	Jul. 31, 2011	Jul. 31, 2010
Stock Option Plans [Abstract]
Options Outstanding, Beginning	8,387,994	9,543,624	9,996,250
Options Outstanding, Granted	1,082,979	1,103,202	1,287,948
Options Outstanding, Exercised	(1,379,827)	(2,243,502)	(1,697,980)
Options Outstanding, Canceled	(34,819)	(15,330)	(42,594)
Options Outstanding, Ending	8,056,327	8,387,994	9,543,624
Weighted Average Exercise Price, Outstanding, Beginning	$ 17.72	$ 15.02	$ 13.47
Weighted Average Exercise Price, Granted	$ 34.76	$ 28.61	$ 21.21
Weighted Average Exercise Price, Exercised	$ 11.90	$ 11.55	$ 10.42
Weighted Average Exercise Price, Canceled	$ 27.45	$ 23.60	$ 20.97
Weighted Average Exercise Price, Outstanding, Ending	$ 20.97	$ 17.72	$ 15.02