Derivative Financial Instruments and Hedging Activities - Gross Fair Values of Derivative Assets, Derivative Liabilities, and Margin Deposits (Cash Collateral) (Details) - USD ($) $ in Thousands	Feb. 28, 2023	Aug. 31, 2022
Reconciliation of gross and net fair value of assets and liabilities subject to offsetting arrangements [Line Items]
Derivative Asset, Fair Value, Gross Asset	$ 448,564	$ 517,090
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	432,810	504,355
Derivative Liability, Fair Value, Gross Liability	299,868	390,940
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	282,638	368,041
Not Designated as Hedging Instrument | Commodity derivatives
Reconciliation of gross and net fair value of assets and liabilities subject to offsetting arrangements [Line Items]
Derivative Asset, Fair Value, Gross Asset	391,602	464,167
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	383,122	460,333
Derivative Liability, Fair Value, Gross Liability	288,612	378,291
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	278,656	364,293
Not Designated as Hedging Instrument | Foreign exchange derivatives
Reconciliation of gross and net fair value of assets and liabilities subject to offsetting arrangements [Line Items]
Derivative Asset, Fair Value, Gross Asset	56,962	52,923
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	49,688	44,022
Derivative Liability, Fair Value, Gross Liability	11,256	12,649
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	$ 3,982	$ 3,748