Note 14 - Stock-Based Compensation (Details) - Summary of Stock Option Weighted Average Assumptions	12 Months Ended
	Aug. 31, 2013	Aug. 31, 2012	Aug. 31, 2011
Note 14 - Stock-Based Compensation (Details) - Summary of Stock Option Weighted Average Assumptions [Line Items]
Risk-free interest rate	0.07%	0.06%	0.10%
Expected life (in years)	3 months	3 months	3 months
Expected volatility	9.80%	14.80%	11.90%
Dividend yield	1.38%	1.26%	1.04%
Non-Employee Directors' Stock Option Plan [Member]
Note 14 - Stock-Based Compensation (Details) - Summary of Stock Option Weighted Average Assumptions [Line Items]
Risk-free interest rate	0.89%	0.94%	2.13%
Expected life (in years)	5 years 146 days	5 years 146 days	5 years 146 days
Expected volatility	32.00%	34.00%	31.00%
Dividend yield	1.30%	1.11%	1.18%