Fair Value - Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands		Aug. 31, 2018	May 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets		$ 5,144	$ 11,423
Liabilities		1,569	846
Derivative Instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	[1]	5,144	11,423
Liabilities	[1]	1,569	846
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets		5,144	11,423
Liabilities		1,569	846
Significant Other Observable Inputs (Level 2) | Derivative Instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	[1]	5,144	11,423
Liabilities	[1]	$ 1,569	$ 846

[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 O – Derivative Instruments and Hedging Activities” for additional information regarding our use of derivative instruments.