Consolidated Statements of Changes in Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Equity-based compensation (in shares)	3,284,120	2,167,170	1,133,725
Grant of exchangeability and redemption of limited partnership interests (in shares)	30,998,136	58,024,858	13,190,311
Repurchase of Class A common stock (in shares)	27,087,000	68,253,000
Cantor purchase of Cantor units from BGC Holdings upon redemption of FPUs (in shares)	833,515	4,408,931
Dividends declared per share of common stock (in dollars per share)	$ 0.04	$ 0.04	$ 0.17
Dividends declared and paid per share of common stock (in dollars per share)	$ 0.04	$ 0.04	$ 0.17
Smith Mack
Issuance of Class A common stock and RSUs for acquisitions (in shares)	1,205,767	1,789,018	390,775
Partnership Units
Redemption of FPUs (in shares)	113,203	1,198,131	730,141
Class A Common Stock
Grant of exchangeability and redemption of limited partnership interests (in shares)	30,998,000	58,025,000
Issuance of Class A common stock (net of costs) (in shares)	500,697	417,247	390,570
Repurchase of Class A common stock (in shares)	27,086,884	68,253,498	2,259
Forfeiture of Class A common stock (in shares)	66,693	140,188
Issuance of Class A common stock and RSUs for acquisitions (in shares)	1,206,000	1,789,000