Derivative Financial Instruments - Counterparty Credit Quality with Respect to Fair Value of OTC Derivatives Assets (Details) $ in Thousands	May 31, 2020 USD ($)
Derivative Instruments and Hedging Activities Disclosure [Abstract]
A- or higher	$ 133,783
BBB- to BBB	32,975
BB or lower	336,290
Unrated	240,873
Total OTC derivative assets included in Financial instruments owned	$ 743,921

Fair value of OTC derivatives assets, counterparty credit quality BB or lower.

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Fair value of OTC derivatives assets, counterparty credit quality BBB- to BBB.

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Fair value of OTC derivatives assets, counterparty credit quality unrated.

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Fair Value Of Over Counter Derivatives Assets Counterparty Credit QualityA Or Higher

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OTC Derivative Assets Included In Financial Instruments Owned.

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