Basis of Presentation (Details) (Foreign exchange forward contracts [Member], Derivatives Not Designated as Hedging Instruments [Member], USD $) In Thousands, unless otherwise specified	Aug. 31, 2012	May 31, 2012
Other assets [Member]
Fair value of foreign exchange forward contracts
Foreign exchange forward contracts other assets	$ 0	$ 179
Accrued expenses [Member]
Fair value of foreign exchange forward contracts
Foreign exchange forward contracts accrued expenses	$ 99	$ 0

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

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 17

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4B

-Subparagraph (c)(2)

-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5624163-113959

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant