Note 14. Employee Stock Option and Retirement Plans (Detail) - Summary of Restricted Stock Award (USD $)	1 Months Ended	0 Months Ended		1 Months Ended				12 Months Ended		14 Months Ended
	Jul. 22, 2011	Apr. 14, 2011	Feb. 09, 2010	Apr. 30, 2011	Jan. 31, 2011	Jun. 30, 2010	Oct. 23, 2009	Aug. 31, 2012	Aug. 31, 2011	Jul. 31, 2011
Balance								407,000	261,000
Balance (in Dollars per share)								$ 71.31	$ 61.65
Granted (restricted stock and stock units)	1,092	30,090	90,030	30,090	366	15,000	161,794		154,281	21,102
Granted (restricted stock and stock units) (in Dollars per share)	$ 91.54	$ 99.75	$ 59.42	$ 99.75	$ 95.24	$ 62.49	$ 62.85		$ 87.55
Vested								(14,258)
Vested (in Dollars per share)								$ 69.02
Canceled/forfeited								(10,000)	(8,000)
Canceled/forfeited (in Dollars per share)								$ 77.13	$ 69.41
Balance								383,000	407,000
Balance (in Dollars per share)								$ 71.34	$ 71.31