Derivative Financial Instruments and Hedging Activities - Fair Value of Commodity Derivative Instruments (Details) - USD ($) $ in Thousands	Feb. 28, 2021	Aug. 31, 2020
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	$ 579,671	$ 412,809
Derivative Asset, Fair Value, Gross Asset	1,003,227	358,300
Cash Flow Hedging \| Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	1,154	8,821
Derivative Asset, Fair Value, Gross Asset	$ 11,008	$ 34,052

Fair value, before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

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