Derivative Financial Instruments and Hedging Activities - Purchase and Sale Contracts (Details) - Not Designated as Hedging Instrument t in Thousands, T in Thousands, MMBtu in Thousands, Bushels in Thousands, Barrels in Thousands	Feb. 28, 2021 MMBtu Bushels Barrels T t	Aug. 31, 2020 Barrels T Bushels t MMBtu
Grain and oilseed (bushels) | Long [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | Bushels	851,400	664,673
Grain and oilseed (bushels) | Short [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | Bushels	1,181,716	892,303
Energy products (barrels) | Long [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | Barrels	12,560	10,028
Energy products (barrels) | Short [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | Barrels	11,779	6,570
Processed grain and oilseed (tons) | Long [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	609	657
Processed grain and oilseed (tons) | Short [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	2,320	3,304
Crop nutrients (tons) | Long [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	2	74
Crop nutrients (tons) | Short [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	177	127
Ocean Freight Contracts [Member] | Long [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | t	370	1,140
Ocean Freight Contracts [Member] | Short [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | t	0	95
Natural gas (MMBtu) | Long [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | MMBtu	0	0
Natural gas (MMBtu) | Short [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | MMBtu	200	0