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	Nov. 30, 2019 T Bushels t MMBtu Barrels	Aug. 31, 2019 T Bushels t MMBtu Barrels
Grain and oilseed (bushels) | Long [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | Bushels	546,758	547,096
Grain and oilseed (bushels) | Short [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | Bushels	733,722	717,522
Energy products (barrels) | Long [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | Barrels	9,705	13,895
Energy products (barrels) | Short [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | Barrels	5,363	4,663
Processed grain and oilseed (tons) | Long [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	454	597
Processed grain and oilseed (tons) | Short [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	2,753	2,454
Crop nutrients (tons) | Long [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	73	76
Crop nutrients (tons) | Short [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	29	23
Ocean Freight Contracts [Member] | Long [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | t	200	295
Ocean Freight Contracts [Member] | Short [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | t	55	85
Natural gas (MMBtu) | Long [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | MMBtu	60	130
Natural gas (MMBtu) | Short [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | MMBtu	0	0