Unconsolidated Subsidiaries - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
Aug. 31, 2014	Aug. 31, 2013	May 31, 2008
Schedule of Equity Method Investments [Line Items]
Percentage of ownership in joint venture			50.00%
Equity Method Investment Unconsolidated Subsidiaries Sales Revenues	$ 0	$ 4.0

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 323

-SubTopic 10

-Section 50

-Paragraph 3

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=6382943&loc=d3e33918-111571

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant