Schedule of Derivatives Designated as Cash Flow Hedging Instruments (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Nov. 30, 2017	Nov. 30, 2016	Nov. 30, 2017	Nov. 30, 2016
Derivative [Line Items]
Gain Recognized in OCI (Effective Portion)	$ 2,114	$ 7,317	$ 8,912	$ 8,050
Gain (Loss) Reclassified from Accumulated OCI (Effective Portion)	5,609	5,270	9,414	4,915
Commodity Contracts
Derivative [Line Items]
Gain Recognized in OCI (Effective Portion)	2,080	7,157	5,814	7,926
Commodity Contracts \| Cost of Goods Sold
Derivative [Line Items]
Gain (Loss) Reclassified from Accumulated OCI (Effective Portion)	5,637	5,737	9,805	5,485
Interest Rate Contracts
Derivative [Line Items]
Gain Recognized in OCI (Effective Portion)	34	160	3,098	124
Interest Rate Contracts \| Interest Expense
Derivative [Line Items]
Gain (Loss) Reclassified from Accumulated OCI (Effective Portion)	$ (28)	$ (467)	$ (391)	$ (570)

The effective portion of net gain (loss) reclassified from accumulated other comprehensive income into income on derivative instruments designated and 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 (c)
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624171-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4D
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624177-113959

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- Definition

The effective portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments that was recognized in other comprehensive income during the current period.

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