Schedule of Gain (Loss) Recognized in Earnings for Economic (Non-Designated) Derivative Financial Instruments (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Aug. 31, 2014	Aug. 31, 2013
Derivative [Line Items]
Gain (Loss) Recognized in Earnings	$ 204	$ 671
Commodity Contracts \| Cost Of Goods Sold
Derivative [Line Items]
Gain (Loss) Recognized in Earnings	(57)	676
Foreign Exchange Contracts \| Miscellaneous Income (Expense)
Derivative [Line Items]
Gain (Loss) Recognized in Earnings	$ 261	$ (5)

Amount of realized and unrealized gain (loss) of derivative instruments not designated or qualifying as hedging instruments.

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

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