Compensation - Units Redeemed in Connection with Issuance of Class A Common Stock (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Share-based Compensation Arrangement by Share-based Payment Award
Number of units redeemed (in shares)	1,274,736	1,072,619	4,922,350	3,817,173
BGC Holdings Units
Share-based Compensation Arrangement by Share-based Payment Award
Number of units redeemed (in shares)	0	100,280	0	116,556
Newmark Holdings Units
Share-based Compensation Arrangement by Share-based Payment Award
Number of units redeemed (in shares)	1,274,736	972,339	4,922,350	3,700,617