Note 15. Stock-Based Compensation (Detail) - Summary of Stock Option Weighted Average Assumptions	12 Months Ended
	Aug. 31, 2012	Aug. 31, 2011	Aug. 31, 2010
Risk-free interest rate	0.94%	2.13%	2.54%
Expected life (months)	5 years 156 days	5 years 156 days	5 years 156 days
Expected volatility	33.60%	31.10%	35.40%
Dividend yield	1.11%	1.18%	1.42%
Employee Stock Purchase Plan [Member]
Risk-free interest rate	0.06%	0.10%	0.12%
Expected life (months)	3 months	3 months	3 months
Expected volatility	14.80%	11.90%	13.80%
Dividend yield	1.26%	1.04%	1.33%