Derivative Financial Instruments and Hedging Activities - Fair Value of Assets and Liabilities Related to Foreign Forward Exchange Contracts Measured on Recurring Basis (Details) - Recurring $ in Thousands	May 31, 2018 USD ($)
Assets:
Forward foreign exchange contracts, Assets	$ 13,662
Liabilities:
Forward foreign exchange contracts, Liabilities	(31,847)
Total	(18,185)
Level 1
Assets:
Forward foreign exchange contracts, Assets	0
Liabilities:
Forward foreign exchange contracts, Liabilities	0
Total	0
Level 2
Assets:
Forward foreign exchange contracts, Assets	13,662
Liabilities:
Forward foreign exchange contracts, Liabilities	(31,847)
Total	(18,185)
Level 3
Assets:
Forward foreign exchange contracts, Assets	0
Liabilities:
Forward foreign exchange contracts, Liabilities	0
Total	$ 0