Note 14. Stock-Based Compensation (Detail) - Estimated Fair Value for the Employee Stock Purchase plan	3 Months Ended		6 Months Ended		12 Months Ended
	Feb. 29, 2012	Feb. 28, 2011	Feb. 29, 2012	Feb. 28, 2011	Aug. 31, 2011
Risk-free interest rate			0.94%		2.13%
Expected volatility			33.60%		31.10%
Dividend yield		1.25%	1.11%	1.25%	1.18%
Employee Stock Purchase Plan Fair Value Determinations [Member]
Risk-free interest rate	0.05%	0.14%	0.03%	0.14%
Expected volatility	12.40%	9.40%	15.10%	9.60%
Dividend yield	1.20%	1.00%	1.20%	1.10%