Related Party Transactions - Additional Information (Detail) (USD $)	12 Months Ended
May 31, 2014	May 31, 2013	May 31, 2012
Related Party Transaction [Line Items]
Net sales to affiliates	$ 31,441,000	$ 19,568,000	$ 22,006,000
Purchases from affiliates	9,387,000	4,930,000	4,313,000
Receivables from affiliates	4,124,000	4,466,000
Payable to affiliates	$ 12,716,000	$ 11,777,000

For an unclassified balance sheet, amounts due from related parties including affiliates, employees, joint ventures, officers and stockholders, immediate families thereof, and pension funds.

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Carrying amount as of the balance sheet date of obligations due all related parties.

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- Definition

Amount of revenue, fees and commissions earned from transactions between (a) a parent company and its subsidiaries; (b) subsidiaries of a common parent; (c) an entity and trusts for the benefit of employees, for example, but not limited to, pension and profit-sharing trusts that are managed by or under the trusteeship of the entity's management; (d) an entity and its principal, owners, management, or members of their immediate families; and (e) affiliates.

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