Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	May. 31, 2015	May. 31, 2014
Assets
Supplemental executive retirement plan:	$ 3,521	$ 3,418
Fair Value, Measurements, Recurring
Assets
Total assets measured at fair value	3,505	3,427
Fair Value, Measurements, Recurring \| Supplemental executive retirement plan \| Money market funds
Assets
Supplemental executive retirement plan:	166	323
Fair Value, Measurements, Recurring \| Supplemental executive retirement plan \| Mutual Funds
Assets
Supplemental executive retirement plan:	3,355	3,095
Fair Value, Measurements, Recurring \| Foreign exchange forward contracts
Assets
Foreign exchange forward contracts	(16)	9
Quoted Prices in Active Markets for Identical Instruments (Level 1) \| Fair Value, Measurements, Recurring
Assets
Total assets measured at fair value	3,521	3,418
Quoted Prices in Active Markets for Identical Instruments (Level 1) \| Fair Value, Measurements, Recurring \| Supplemental executive retirement plan \| Money market funds
Assets
Supplemental executive retirement plan:	166	323
Quoted Prices in Active Markets for Identical Instruments (Level 1) \| Fair Value, Measurements, Recurring \| Supplemental executive retirement plan \| Mutual Funds
Assets
Supplemental executive retirement plan:	3,355	3,095
Significant Other Observable Inputs (Level 2) \| Fair Value, Measurements, Recurring
Assets
Total assets measured at fair value	(16)	9
Significant Other Observable Inputs (Level 2) \| Fair Value, Measurements, Recurring \| Foreign exchange forward contracts
Assets
Foreign exchange forward contracts	(16)	9
Supplemental Executive Retirement Plan [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Accrued Expense	$ 3,521	$ 3,418

Accrued Expense

No definition available.

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- Definition

This element represents the aggregate of the assets reported on the balance sheet at period end measured at fair value on a recurring basis by the entity. This element is intended to be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements.

+ References

No definition available.

+ Details

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- References

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- Definition

+ References

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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.

+ Details

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- Definition

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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