Compensation - Summary of Outstanding LPUs Held by BGC Employees with Stated Vesting (Detail) - LPUs - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate estimated grant date fair value	$ 0	$ 194,951
BGC Holdings LPUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate estimated grant date fair value	0	47,222
Newmark Holdings LPUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate estimated grant date fair value	$ 0	$ 98