Derivatives and Hedging (Details) - Not Designated as Hedging Instrument [Member] - Foreign Exchange Contract [Member] - USD ($) $ in Millions	3 Months Ended
Aug. 31, 2015	Aug. 31, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Derivative notional amount	$ 16.2	$ 24.7
Unrealized gain (loss)	$ 1.1	$ (0.3)

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 12

-Section 13

-Sentence Column B

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Amount of net unrealized gain (loss) related to the change in fair value of foreign currency exchange rate derivatives designated as cash flow hedging instruments. Recorded in accumulated other comprehensive income to the extent that the cash flow hedge is determined to be effective.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4C

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=56946850&loc=SL5624171-113959

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- Details

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