Note 15 - Stock-Based Compensation (Tables)

12 Months Ended

Aug. 31, 2014

Note 15 - Stock-Based Compensation (Tables) [Line Items]

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

	2014				2013				2012
Term structure of risk-free interest rate		0.01%	-	2.6%		0.16%	-	1.91%		0.13%	-	2.41%
Expected life (years)		7.6	-	7.8		7.6	-	7.8		7.6	-	9.1
Term structure of volatility		23%	-	33%		24%	-	33%		29%	-	36%
Dividend yield			1.35%				1.30%				1.16%
Weighted average estimated fair value			$29.64				$26.87				$32.34
Weighted average exercise price			$106.69				$92.22				$93.86
Fair value as a percentage of exercise price			27.8%				29.1%				34.5%

Non-Employee Stock Option Plan [Member]

Note 15 - Stock-Based Compensation (Tables) [Line Items]

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

Risk-free interest rate	1.66	%
Expected life (in years)	5.4
Expected volatility	28.9	%
Dividend yield	1.35	%

Risk-free interest rate	0.89	%
Expected life (years)	5.4
Expected volatility	32	%
Dividend yield	1.30	%

Risk-free interest rate	0.94	%
Expected life (years)	5.4
Expected volatility	34	%
Dividend yield	1.11	%

Employee Stock Purchase Plan [Member]

Note 15 - Stock-Based Compensation (Tables) [Line Items]

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

	2014			2013			2012
Risk-free interest rate		0.04	%		0.07	%		0.06	%
Expected life (months)		3			3			3
Expected volatility		9.8	%		9.8	%		14.8	%
Dividend yield		1.38	%		1.38	%		1.26	%