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Collateralized Transactions - Additional Information (Detail) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Securities Financing Transaction [Line Items]
Securities loaned		$ 13,902,000
CF & Co [Member]
Securities Financing Transaction [Line Items]
Repurchase agreements	$ 0	0
Securities loaned	$ 0	$ 13,900,000
Stated interest rate		2.45%
CF & Co [Member] | Securities Financing Transaction, Fair Value [Member]
Securities Financing Transaction [Line Items]
Securities loaned		$ 13,900,000
CF & Co [Member] | Securities Financing Transaction, Fair Value [Member] | Fair Value [Member]
Securities Financing Transaction [Line Items]
Securities loaned		$ 13,900,000

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Contractual interest rate for funds borrowed, under the debt agreement.

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Amount, after the effects of master netting arrangements, of securities loaned to entities in exchange for collateral. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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