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, 2012	Aug. 31, 2011
Derivative [Line Items]
Gain (Loss) Recognized in Earnings	$ 950	$ (851)
Commodity Contracts \| Cost Of Goods Sold
Derivative [Line Items]
Gain (Loss) Recognized in Earnings	1,813	(877)
Foreign Exchange Contracts \| Miscellaneous Income (Expense)
Derivative [Line Items]
Gain (Loss) Recognized in Earnings	$ (863)	$ 26

Net gain (loss) from the increase (decrease) in fair value of derivative instrument not designated as hedging instrument.

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=7476318&loc=SL5624171-113959

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 45

-Subparagraph b(1)(b)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

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