Derivative Financial Instruments and Hedging Activities - Derivative Assets and Liabilities Not Designated as Hedging Instruments (Details) - Not Designated as Hedging Instrument - USD ($) $ in Thousands	12 Months Ended
	Aug. 31, 2019	Aug. 31, 2018	Aug. 31, 2017
Derivative [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	$ 131,091	$ 139,967	$ 184,366
Commodity derivatives | Cost of goods sold
Derivative [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	125,323	162,321	168,569
Foreign exchange derivatives | Cost of goods sold
Derivative [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	4,228	(26,010)	(13,140)
Foreign exchange derivatives | Marketing, general and administrative
Derivative [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	(1,229)	596	(1,604)
Interest rate derivatives | Interest expense
Derivative [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	0	(1)	8
Embedded derivative asset | Other income (loss)
Derivative [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	$ 2,769	$ 3,061	$ 30,533