Compensation - Compensation Expense Related to Restricted Stock Unit Held by BGC Employees (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Compensation Related Costs [Abstract]
RSU amortization	$ 101,673	$ 79,960	$ 16,559

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

No definition available.

Name:	bgcg_ShareBasedCompensationArrangementByShareBasedPaymentAwardRestrictedStockUnitsAmortization
Namespace Prefix:	bgcg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration