Derivative Financial Instruments and Hedging Activities - Fair Value of Derivative Instruments Located on Consolidated Balance Sheets (Details) - Forward foreign exchange contracts - USD ($) $ in Thousands	May 31, 2018	Aug. 31, 2017
Designated as Hedging Instruments | Prepaid expenses and other current assets
Derivatives, Fair Value [Line Items]
Forward foreign exchange contracts, Asset Derivatives	$ 7,022	$ 8,380
Designated as Hedging Instruments | Accrued expenses
Derivatives, Fair Value [Line Items]
Forward foreign exchange contracts, Liability Derivatives	9,607	1,408
Not Designated as Hedging Instrument | Prepaid expenses and other current assets
Derivatives, Fair Value [Line Items]
Forward foreign exchange contracts, Asset Derivatives	6,640	31,280
Not Designated as Hedging Instrument | Accrued expenses
Derivatives, Fair Value [Line Items]
Forward foreign exchange contracts, Liability Derivatives	$ 22,240	$ 9,131