Consolidated Statements of Changes in Equity (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Equity-based compensation (in shares)	14,758,605	3,284,120	2,167,170
Grant of exchangeability and redemption of limited partnership interests (in shares)	29,118,664	30,998,136	58,024,858
Repurchase of Class A common stock (in shares)	24,220,000	27,087,000
Cantor purchase of Cantor units from BGC Holdings upon redemption of FPUs (in shares)	6,368,964	833,515	4,408,931
Dividends declared per share of common stock (in dollars per share)	$ 0.04	$ 0.04	$ 0.04
Dividends declared and paid per share of common stock (in dollars per share)	$ 0.04	$ 0.04	$ 0.04
Restricted stock awards	38,610,233	0
Conversion of Class B common stock to Class A common stock (in shares)	405,801
Reallocation Of Treasury Shares During Period, Value, Corporate Conversion	$ 0
Cancellation of BGC Partners, Inc. Treasury Stock due to Corporate Conversion (in shares)	156,386,616
Additional Paid-in Capital
Reallocation Of Treasury Shares During Period, Value, Corporate Conversion	$ (751,768)
Treasury Stock
Reallocation Of Treasury Shares During Period, Value, Corporate Conversion	$ 753,331
Smith Mack
Issuance of Class A common stock and RSUs for acquisitions (in shares)	5,504,698	1,205,767
Partnership Units
Redemption of FPUs (in shares)	184,990	113,203	1,198,131
Class A Common Stock
Grant of exchangeability and redemption of limited partnership interests (in shares)	30,754,000	30,998,000
Issuance of Class A common stock (net of costs) (in shares)	518,191	500,697	417,247
Repurchase of Class A common stock (in shares)	23,250,551	27,086,884	68,253,498
Forfeiture of Class A common stock (in shares)	1,428,363	66,693	140,188
Issuance of Class A common stock and RSUs for acquisitions (in shares)	4,566,000	1,206,000
Common stock, shares issued (in shares)	20,500,000	20,900,000
Class A Common Stock | Common Stock
Reallocation Of Treasury Shares During Period, Value, Corporate Conversion	$ (1,563)
Class A Common Stock | Smith Mack
Issuance of Class A common stock and RSUs for acquisitions (in shares)			1,789,018
Class B Common Stock
Issuance of Class A common stock (net of costs) (in shares)	64,000,000	0
Common stock, shares issued (in shares)	63,974,374