Compensation - Summary of Compensation Expense Related to Amortization of LPUs Held by BGC Employees (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
LPU amortization	$ 0	$ 40,878	$ 73,734
Stated vesting schedule
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
LPU amortization	0	40,848	74,561
Post-termination payout
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
LPU amortization	$ 0	$ 30	$ (827)