Schedule of Summary of Derivative Hedges (Detail) $ in Thousands	3 Months Ended
	Aug. 31, 2017 USD ($)
Commodity Contracts | Derivatives Not Designated As Hedging Instruments
Derivative [Line Items]
Notional Amount	$ 20,346
Commodity Contracts | Derivatives Not Designated As Hedging Instruments | Minimum
Derivative [Line Items]
Maturity Date	2017-09
Commodity Contracts | Derivatives Not Designated As Hedging Instruments | Maximum
Derivative [Line Items]
Maturity Date	2019-02
Foreign Currency Contracts | Derivatives Not Designated As Hedging Instruments
Derivative [Line Items]
Notional Amount	$ 4,921
Maturity Date	2017-09
Cash Flow Hedges | Commodity Contracts
Derivative [Line Items]
Notional Amount	$ 25,372
Cash Flow Hedges | Commodity Contracts | Minimum
Derivative [Line Items]
Maturity Date	2017-09
Cash Flow Hedges | Commodity Contracts | Maximum
Derivative [Line Items]
Maturity Date	2019-06
Cash Flow Hedges | Interest Rate Contracts
Derivative [Line Items]
Notional Amount	$ 18,221
Maturity Date	2019-09