Compensation - Units Redeemed in Connection with Issuance of Class A Common Stock (Details) - shares	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award
Number of units redeemed (in shares)	9,835,548	11,360,611	9,376,796
BGC Holdings Units
Share-based Compensation Arrangement by Share-based Payment Award
Number of units redeemed (in shares)	0	127,960	142,194
Newmark Holdings Units
Share-based Compensation Arrangement by Share-based Payment Award
Number of units redeemed (in shares)	9,835,548	11,232,651	9,234,602