Stockholders' Equity (Dividends) (Details 5) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
Aug. 31, 2015	May. 31, 2015	Feb. 28, 2015	Nov. 30, 2014	Aug. 31, 2014	May. 31, 2014	Feb. 28, 2014	Nov. 30, 2013
Stockholders' Equity [Abstract]
Dividend Declaration Date	Jul. 16, 2015	Apr. 15, 2015	Jan. 21, 2015	Oct. 16, 2014	Jul. 23, 2014	Apr. 17, 2014	Jan. 22, 2014	Oct. 17, 2013
Dividend Cash Payment Date	Sep. 01, 2015	Jun. 01, 2015	Mar. 02, 2015	Dec. 01, 2014	Sep. 02, 2014	Jun. 02, 2014	Mar. 03, 2014	Dec. 02, 2013
Date of Record for Dividend Payment	Aug. 14, 2015	May 15, 2015	Feb. 13, 2015	Nov. 14, 2014	Aug. 15, 2014	May 15, 2014	Feb. 14, 2014	Nov. 15, 2013
Total of Cash Dividends Declared	$ 15,980	$ 15,988	$ 16,020	$ 15,973	$ 16,289	$ 16,686	$ 16,976	$ 17,221
Dividend per Share	$ 0.08	$ 0.08	$ 0.08	$ 0.08	$ 0.08	$ 0.08	$ 0.08	$ 0.08

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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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The per share amount of a dividend declared, but not paid, as of the financial reporting date.

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Carrying value as of the balance sheet date of dividends declared but unpaid on equity securities issued by the entity and outstanding.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.15(5))

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.15(5))

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 15

-Subparagraph a

-Article 7

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

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Date the holder must own the stock to be entitled to the dividend, in CCYY-MM-DD format.

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