Related Party Transactions - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
May 31, 2016	May 31, 2015	May 31, 2014
Related Party Transaction [Line Items]
Net sales to affiliates	$ 32,496	$ 32,277	$ 31,441
Purchases from affiliates	15,737	8,021	$ 9,387
Receivables from affiliates	5,152	5,826
Payable to affiliates	$ 107	$ 11,528

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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 850
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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Carrying amount as of the balance sheet date of obligations due all related parties.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Topic 850
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-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864

Reference 2: http://www.xbrl.org/2003/role/presentationRef
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Purchases during the period (excluding transactions that are eliminated in consolidated or combined financial statements) with related party.

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+ References

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