Schedule of Summary of Derivative Hedges (Detail) $ in Thousands	6 Months Ended
	Nov. 30, 2017 USD ($)
Commodity Contracts | Derivatives Not Designated As Hedging Instruments
Derivative [Line Items]
Notional Amount	$ 25,427
Commodity Contracts | Derivatives Not Designated As Hedging Instruments | Minimum
Derivative [Line Items]
Maturity Date	2017-12
Commodity Contracts | Derivatives Not Designated As Hedging Instruments | Maximum
Derivative [Line Items]
Maturity Date	2019-05
Foreign Currency Contracts | Derivatives Not Designated As Hedging Instruments
Derivative [Line Items]
Notional Amount	$ 5,469
Foreign Currency Contracts | Derivatives Not Designated As Hedging Instruments | Minimum
Derivative [Line Items]
Maturity Date	2017-12
Foreign Currency Contracts | Derivatives Not Designated As Hedging Instruments | Maximum
Derivative [Line Items]
Maturity Date	2018-06
Cash Flow Hedges | Commodity Contracts
Derivative [Line Items]
Notional Amount	$ 22,011
Cash Flow Hedges | Commodity Contracts | Minimum
Derivative [Line Items]
Maturity Date	2017-12
Cash Flow Hedges | Commodity Contracts | Maximum
Derivative [Line Items]
Maturity Date	2019-06
Cash Flow Hedges | Interest Rate Contracts
Derivative [Line Items]
Notional Amount	$ 18,212
Maturity Date	2019-09