Fair Value of Foreign Exchange Forward Contracts (Detail) - Derivatives Not Designated as Hedging Instruments - Foreign exchange forward contracts - USD ($) $ in Thousands	12 Months Ended
May. 31, 2015	May. 31, 2014	May. 31, 2013
Selling, General and Administrative Expenses
Derivatives, Fair Value [Line Items]
Gain (Loss) on Foreign Currency Derivative Instruments Not Designated as Hedging Instruments	$ 1,210	$ (269)	$ (306)
Other assets
Foreign Currency Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Foreign exchange forward contracts other assets	$ (16)	$ 9

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- References

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Fair value as of the balance sheet date of all foreign currency derivatives not designated as hedging instruments.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 45

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958

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Amount of gain (loss) recognized in earnings in the period from the increase (decrease) in fair value of foreign currency derivatives not designated as hedging instruments.

+ 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 (e)

-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5624171-113959

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

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-Section 50

-Paragraph 4A

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5618551-113959

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