Fair Value - Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands		Nov. 30, 2020	May 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets			$ 2,800
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets		$ 167,906	181
Liabilities		1,951	8,777
Fair Value, Measurements, Recurring | Derivative Instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	[1]	24,056	181
Liabilities	[1]	1,951	8,777
Fair Value, Measurements, Recurring | Investment in Nikola
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	[2]	143,850
Fair Value, Measurements, Recurring | Quoted Prices In Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets		143,850
Fair Value, Measurements, Recurring | Quoted Prices In Active Markets (Level 1) | Investment in Nikola
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	[2]	143,850
Fair Value, Measurements, Recurring | Fair Value Inputs Level2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets		24,056	181
Liabilities		1,951	8,777
Fair Value, Measurements, Recurring | Fair Value Inputs Level2 | Derivative Instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	[1]	24,056	181
Liabilities	[1]	$ 1,951	$ 8,777

[1] The fair value of our derivative instruments is based on the present value of the expected future cash flows considering the risks involved, including non-performance risk, and using discount rates appropriate for the respective maturities.  Market observable, Level 2 inputs are used to determine the present value of the expected future cash flows.  Refer to “NOTE P – Derivative Instruments and Hedging Activities” for additional information regarding our use of derivative instruments.

[2] The fair value of the investment in Nikola is based on the share price of Nikola common stock at November 30, 2020.