Derivative Instruments and Hedging Activities - Schedule of Fair Value of Derivative Instruments (Detail) - USD ($) $ in Thousands	Nov. 30, 2019	May 31, 2019
Derivative [Line Items]
Asset Derivatives at Fair Value	$ 969	$ 2,414
Liability Derivatives at Fair Value	6,805	12,238
Derivatives Designated As Hedging Instruments
Derivative [Line Items]
Asset Derivatives at Fair Value	9	5
Liability Derivatives at Fair Value	5,020	8,584
Derivatives Designated As Hedging Instruments | Commodity Contracts | Accounts Payable
Derivative [Line Items]
Liability Derivatives at Fair Value	4,569	8,383
Derivatives Designated As Hedging Instruments | Commodity Contracts | Receivables
Derivative [Line Items]
Asset Derivatives at Fair Value	9	5
Derivatives Designated As Hedging Instruments | Commodity Contracts | Other Liabilities
Derivative [Line Items]
Liability Derivatives at Fair Value	451	201
Derivatives Not Designated As Hedging Instruments
Derivative [Line Items]
Asset Derivatives at Fair Value	960	2,409
Liability Derivatives at Fair Value	1,785	3,654
Derivatives Not Designated As Hedging Instruments | Commodity Contracts
Derivative [Line Items]
Asset Derivatives at Fair Value	960	2,409
Liability Derivatives at Fair Value	1,710	3,634
Derivatives Not Designated As Hedging Instruments | Commodity Contracts | Accounts Payable
Derivative [Line Items]
Liability Derivatives at Fair Value	1,487	3,568
Derivatives Not Designated As Hedging Instruments | Commodity Contracts | Receivables
Derivative [Line Items]
Asset Derivatives at Fair Value	953	2,347
Derivatives Not Designated As Hedging Instruments | Commodity Contracts | Other Assets
Derivative [Line Items]
Asset Derivatives at Fair Value	7	62
Derivatives Not Designated As Hedging Instruments | Commodity Contracts | Other Liabilities
Derivative [Line Items]
Liability Derivatives at Fair Value	223	66
Derivatives Not Designated As Hedging Instruments | Foreign Currency Exchange Contracts | Accounts Payable
Derivative [Line Items]
Liability Derivatives at Fair Value	$ 75	$ 20