Note 14 - Stock-Based Compensation (Tables)

3 Months Ended

Nov. 30, 2013

Note 14 - Stock-Based Compensation (Tables) [Line Items]

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]

	Three Months Ended November 30,
	2013				2012
Term structure of risk-free interest rate		0.08%	-	2.61%		0.16%	-	1.91%
Expected life (in years)		7.6	-	7.8		7.6	-	7.8
Term structure of volatility		23%	-	33%		24%	-	33%
Dividend yield			1.35	%			1.30	%
Weighted average estimated fair value		$	31.78			$	26.87
Weighted average exercise price		$	109.49			$	92.22
Fair value as a percentage of exercise price			29.0	%			29.1	%

Employee Stock Purchase Plan [Member]

Note 14 - Stock-Based Compensation (Tables) [Line Items]

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]

	Three Months Ended November 30,
	2013		2012
Risk-free interest rate	0.04	%	0.10	%
Expected life (in months)	3		3
Expected volatility	8.66	%	10	%
Dividend yield	1.37	%	1.32	%