Compensation - Activity Associated with Limited Partnership Units Awarded to BGC Employees (Detail) - shares	3 Months Ended
Mar. 31, 2025	Mar. 31, 2024
LPUs \| Newmark Holdings LPUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of units, redeemed (in shares)	99,000	61,000

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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+ Details