Derivatives - Narrative (Detail) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Replacement cost of contracts in a gain position	$ 5.0	$ 3.6

The replacement cost of derivative contracts in a gain or asset position.

No definition available.

Name:	bgcp_DerivativeContractInGainPositionReplacementCost
Namespace Prefix:	bgcp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant