Compensation - Summary of Outstanding LPUs Held by BGC Employees with Stated Vesting (Detail) - LPUs - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Mar. 31, 2023	Jun. 30, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate estimated grant date fair value	$ 192,183	$ 194,951
BGC Holdings LPUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate estimated grant date fair value	47,130	47,222
Newmark Holdings LPUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate estimated grant date fair value	$ 87	$ 98