Derivative Financial Instruments and Hedging Activities - Fair Value of Derivative Instruments Located on Consolidated Balance Sheets (Details) - Forward foreign exchange contracts - USD ($) $ in Thousands	Nov. 30, 2018	Aug. 31, 2018
Designated as Hedging Instruments | Prepaid expenses and other current assets
Derivatives, Fair Value [Line Items]
Forward foreign exchange contracts, Asset Derivatives	$ 915	$ 225
Designated as Hedging Instruments | Accrued expenses
Derivatives, Fair Value [Line Items]
Forward foreign exchange contracts, Liability Derivatives	12,922	13,364
Not Designated as Hedging Instrument | Prepaid expenses and other current assets
Derivatives, Fair Value [Line Items]
Forward foreign exchange contracts, Asset Derivatives	4,364	10,125
Not Designated as Hedging Instrument | Accrued expenses
Derivatives, Fair Value [Line Items]
Forward foreign exchange contracts, Liability Derivatives	$ 23,948	$ 46,171