Derivative Financial Instruments and Hedging Activities - Derivative Instruments Designated as Hedging Instruments (Details) - USD ($) $ in Thousands	Aug. 31, 2018	Aug. 31, 2017
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	$ 445,755	$ 313,261
Gross Amounts Recognized	$ 352,029	$ 249,661

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.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 20
-Section 50
-Paragraph 4D
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226000-175313

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