Compensation - Compensation Expense Related to Restricted Stock Unit Held by BGC Employees (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Share-Based Payment Arrangement [Abstract]
RSU amortization	$ 33,877	$ 29,925	$ 115,723	$ 70,621

Share based compensation arrangement by share based payment award restricted stock units amortization.

No definition available.

Name:	bgcp_ShareBasedCompensationArrangementByShareBasedPaymentAwardRestrictedStockUnitsAmortization
Namespace Prefix:	bgcp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration