Limited Partnership Interests in BGC Holdings and Newmark Holdings - Narrative (Detail)		3 Months Ended
Jul. 01, 2023 shares	Mar. 31, 2025 partnership installment
Related Party Transaction [Line Items]
Number of operating partnerships \| partnership		2
Number of installments \| installment		4
Conversion of stock, shares converted (in shares)	64,000,000
Minimum number of shares required to be issued (in shares)	75,000,000.0
LPUs
Related Party Transaction [Line Items]
Limited partnership interests exchange ratio		0.9271
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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