Treasury Stock (Details) - Schedule of repurchase of common stock (USD $) In Millions, unless otherwise specified	1 Months Ended	6 Months Ended
Nov. 30, 2013	Sep. 30, 2010	Nov. 30, 2013
Schedule of repurchase of common stock [Abstract]
September 2010		$ 44.0
Less repurchases made under this authorization	(30.6)
Remaining Board authorization at November 30, 2013	$ 13.4		$ 13.4

Equity impact of the cost of common and preferred stock that were repurchased during the period. Recorded using the par value method.

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 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 3: 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 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 30

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6405813&loc=d3e23239-112655

Name:	us-gaap_TreasuryStockValueAcquiredParValueMethod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration