Related Party Transactions - Service Agreements (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2025	Mar. 31, 2024
Related Party Transaction [Line Items]
Total revenues	$ 664,240	$ 578,614
Tower Bridge International Services LP \| BGC Partners, Inc.
Related Party Transaction [Line Items]
Company ownership of Tower Bridge (as a percent)	52.00%
Tower Bridge International Services LP \| Cantor
Related Party Transaction [Line Items]
Ownership percentage by noncontrolling owners (as a percent)	48.00%
Related Party
Related Party Transaction [Line Items]
Mark-up cost of services (as a percent)	7.50%
Share of net profit (loss) from noncontrolling interest	$ 500	200
Compensation to leased employees	28,100	19,400
Related Party \| Service Agreement with Cantor
Related Party Transaction [Line Items]
Total revenues	4,400	4,400
Service charges	$ 36,700	$ 26,600

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Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

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