Note 14. Stock-Based Compensation (Detail) - Summary of Stock Option Weighted Average Assumptions Of Employee Stock Options (Employee Stock Purchase Plan Fair Value Determinations [Member], USD $)	3 Months Ended	9 Months Ended
	May 31, 2011	May 31, 2012	May 31, 2011
Employee Stock Purchase Plan Fair Value Determinations [Member]
Term structure of risk-free interest rate	0.19% - 1.00%	0.13% - 2.41%	0.18% - 1.88%
Expected life	4.0 years	7.6 - 7.8 years	4.0 - 6.5 years
Term structure of volatility	23% - 35%	30% - 36%	23% - 35%
Dividend yield	1.07%	1.11%	1.25%
Weighted average estimated fair value (in Dollars per share)	$ 23.41	$ 32.08	$ 24.72