Note 11 - Common Stock and Earnings Per Share (Details) - Weighted Average Shares Outstanding (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	May 31, 2014	May 31, 2013	May 31, 2014	May 31, 2013
Basic EPS
Net Income (Numerator) (in Dollars)	$ 51,532	$ 53,367	$ 156,136	$ 147,674
Weighted Average Common Shares (Denominator)	42,166	43,954	42,615	44,028
Per Share Amount (in Dollars per share)	$ 1.22	$ 1.21	$ 3.66	$ 3.35
Diluted EPS
Weighted Average Common Shares (Denominator)	449	531	555	756
Net Income (Numerator) (in Dollars)	$ 51,532	$ 53,367	$ 156,136	$ 147,674
Weighted Average Common Shares (Denominator)	42,615	44,485	43,170	44,784
Per Share Amount (in Dollars per share)	$ 1.21	$ 1.20	$ 3.62	$ 3.30