Limited Partnership Interests in BGC Holdings and Newmark Holdings - Narrative (Detail)		9 Months Ended
Jul. 01, 2023 shares	Sep. 30, 2023 partnership installment
Related Party Transaction [Line Items]
Number of operating partnerships \| partnership		2
Conversion of stock, shares converted (in shares)	64,000,000
Minimum number of shares required to be issued (in shares)	75,000,000
Number of installments \| installment		4
LPUs
Related Party Transaction [Line Items]
Limited partnership interests exchange ratio		0.9243
Newmark Holdings
Related Party Transaction [Line Items]
Calculation of contribution ratio, denominator		2.2
Limited partnership interest, conversion ratio		1
Percentage of preferred partnership units awarded		0.6875%
Percentage of preferred partnership units awarded per calendar year		2.75%
BGC Holdings
Related Party Transaction [Line Items]
Limited partnership interest, conversion ratio		1
Percentage of preferred partnership units awarded		0.6875%
Percentage of preferred partnership units awarded per calendar year		2.75%

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The number of shares converted in a noncash (or part noncash) transaction. Noncash is defined as transactions during a period that do not result in cash receipts or cash payments in the period. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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