Compensation - Units Redeemed in Connection with Issuance of Class A Common Stock (Details) - shares	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Share-based Compensation Arrangement by Share-based Payment Award
Number of units redeemed (in shares)	3,647,613	2,744,554
BGC Holdings Units
Share-based Compensation Arrangement by Share-based Payment Award
Number of units redeemed (in shares)	0	16,276
Newmark Holdings Units
Share-based Compensation Arrangement by Share-based Payment Award
Number of units redeemed (in shares)	3,647,613	2,728,278