Note 12 - Stockholders' Equity (Details) - Dividends Declared During the Period (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Aug. 31, 2013
August 15, 2013 Declaration Date [Member]
Note 12 - Stockholders' Equity (Details) - Dividends Declared During the Period [Line Items]
Dividends Per Share of Common Stock	$ 0.35
Record Date	Aug. 31, 2013
Total $ Amount (in Dollars)	$ 15,164
Payment Date	Sep. 17, 2013
May 14, 2013 Declaration Date [Member]
Note 12 - Stockholders' Equity (Details) - Dividends Declared During the Period [Line Items]
Dividends Per Share of Common Stock	$ 0.35
Record Date	May 31, 2013
Total $ Amount (in Dollars)	15,413
Payment Date	Jun. 18, 2013
February 21, 2013 Declaration Date [Member]
Note 12 - Stockholders' Equity (Details) - Dividends Declared During the Period [Line Items]
Dividends Per Share of Common Stock	$ 0.31
Record Date	Feb. 28, 2013
Total $ Amount (in Dollars)	13,510
Payment Date	Mar. 19, 2013
November 15, 2012 Declaration Date [Member]
Note 12 - Stockholders' Equity (Details) - Dividends Declared During the Period [Line Items]
Dividends Per Share of Common Stock	$ 0.31
Record Date	Nov. 30, 2012
Total $ Amount (in Dollars)	13,746
Payment Date	Dec. 18, 2012
August 8, 2012 Declaration Date [Member]
Note 12 - Stockholders' Equity (Details) - Dividends Declared During the Period [Line Items]
Dividends Per Share of Common Stock	$ 0.31
Record Date	Aug. 31, 2012
Total $ Amount (in Dollars)	13,727
Payment Date	Sep. 18, 2012
May 8, 2012 Declaration Date [Member]
Note 12 - Stockholders' Equity (Details) - Dividends Declared During the Period [Line Items]
Dividends Per Share of Common Stock	$ 0.31
Record Date	May 31, 2012
Total $ Amount (in Dollars)	13,893
Payment Date	Jun. 19, 2012
February 14, 2012 Declaration Date [Member]
Note 12 - Stockholders' Equity (Details) - Dividends Declared During the Period [Line Items]
Dividends Per Share of Common Stock	$ 0.27
Record Date	Feb. 29, 2012
Total $ Amount (in Dollars)	12,085
Payment Date	Mar. 20, 2012
November 10, 2011 Declaration Date [Member]
Note 12 - Stockholders' Equity (Details) - Dividends Declared During the Period [Line Items]
Dividends Per Share of Common Stock	$ 0.27
Record Date	Nov. 30, 2011
Total $ Amount (in Dollars)	12,181
Payment Date	Dec. 20, 2011
August 11, 2011 Declaration Date [Member]
Note 12 - Stockholders' Equity (Details) - Dividends Declared During the Period [Line Items]
Dividends Per Share of Common Stock	$ 0.27
Record Date	Aug. 31, 2011
Total $ Amount (in Dollars)	12,165
Payment Date	Sep. 20, 2011
May 9, 2011 Declaration Date [Member]
Note 12 - Stockholders' Equity (Details) - Dividends Declared During the Period [Line Items]
Dividends Per Share of Common Stock	$ 0.27
Record Date	May 31, 2011
Total $ Amount (in Dollars)	12,374
Payment Date	Jun. 21, 2011
February 9, 2011 Declaration Date [Member]
Note 12 - Stockholders' Equity (Details) - Dividends Declared During the Period [Line Items]
Dividends Per Share of Common Stock	$ 0.23
Record Date	Feb. 28, 2011
Total $ Amount (in Dollars)	10,612
Payment Date	Mar. 15, 2011
November 10, 2010 Declaration Date [Member]
Note 12 - Stockholders' Equity (Details) - Dividends Declared During the Period [Line Items]
Dividends Per Share of Common Stock	$ 0.23
Record Date	Nov. 30, 2010
Total $ Amount (in Dollars)	10,660
Payment Date	Dec. 21, 2010
August 10, 2010 Declaration Date [Member]
Note 12 - Stockholders' Equity (Details) - Dividends Declared During the Period [Line Items]
Dividends Per Share of Common Stock	$ 0.23
Record Date	Aug. 31, 2010
Total $ Amount (in Dollars)	$ 10,586
Payment Date	Sep. 21, 2010