Note 12 - Stockholders' Equity (Details) - Dividends Declared During the Period (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
Nov. 30, 2014
November 12,2014 Declaration Date [Member]
Note 12 - Stockholders' Equity (Details) - Dividends Declared During the Period [Line Items]
Dividends Per Share of Common Stock	$ 0.39
Record Date	Nov. 28, 2014
Total $ Amount	$ 16,216
Payment Date	Dec. 16, 2014
August 14,2014 Declaration Date [Member]
Note 12 - Stockholders' Equity (Details) - Dividends Declared During the Period [Line Items]
Dividends Per Share of Common Stock	$ 0.39
Record Date	Aug. 29, 2014
Total $ Amount	16,299
Payment Date	Sep. 16, 2014
May 5, 2014 Declaration Date [Member]
Note 12 - Stockholders' Equity (Details) - Dividends Declared During the Period [Line Items]
Dividends Per Share of Common Stock	$ 0.39
Record Date	May 30, 2014
Total $ Amount	16,386
Payment Date	Jun. 17, 2014
February 11, 2014 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	Feb. 28, 2014
Total $ Amount	14,827
Payment Date	Mar. 18, 2014
November 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	Nov. 29, 2013
Total $ Amount	15,046
Payment Date	Dec. 17, 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	$ 15,164
Payment Date	Sep. 17, 2013

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Date the declared dividend will be paid, in CCYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 50

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4304-108586

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Amount of paid and unpaid cash dividends declared for classes of stock, for example, but not limited to, common and preferred.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.3-04)

-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 405

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6957935&loc=d3e64057-112817

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