Derivative Financial Instruments and Hedging Activities - Schedule of Derivatives Instruments Statements of Financial Performance and Financial Position, Location (Details) - Designated as Hedging Instrument - Long-term debt - USD ($) $ in Thousands	May 31, 2019	Aug. 31, 2018
Derivative [Line Items]
Carrying Amount of Hedged Liabilities	$ 470,419	$ 485,548
Cumulative Amount of Fair Value Hedging Adjustments Included in the Carrying Amount of Hedged Liabilities	$ 24,581	$ 9,452