Note 14 - Stock-based Compensation (Details) - Summary of Stock Option Weighted Average Assumptions, Employee Stock Purchase Plan (2008 Employee Stock Purchase Plan [Member])	3 Months Ended		6 Months Ended
	Feb. 28, 2015	Feb. 28, 2014	Feb. 28, 2015	Feb. 28, 2014
2008 Employee Stock Purchase Plan [Member]
Note 14 - Stock-based Compensation (Details) - Summary of Stock Option Weighted Average Assumptions, Employee Stock Purchase Plan [Line Items]
Risk-free interest rate	0.03%	0.05%	0.02%	0.05%
Expected life (in months)	3 years	3 years	3 years	3 years
Expected volatility	8.10%	10.30%	8.30%	9.60%
Dividend yield	1.13%	1.23%	1.17%	1.29%