Stock Transactions and Unit Redemptions - Gross Unit Redemptions and Share Repurchases of Class A Common Stock Table Footnote (Details) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Class of Stock [Line Items]
Aggregate purchase price of Class A common stock	$ 262,211	$ 114,580	$ 103,888
Shares withheld to satisfy tax liabilities (in shares)		1.0
Shares withheld for tax withholding obligation (dollars per share)		$ 5.21
Class A Common Stock
Class of Stock [Line Items]
Repurchase of Class A shares including shares withheld for RSAs (in shares)	36.2
Aggregate purchase price of Class A common stock	$ 300,500	$ 119,600
Weighted-average price of Class A common stock (in dollars per share)	$ 8.30	$ 4.94
Share-based payment arrangement, decrease for tax withholding obligation	$ 41,000	$ 3,900
Cantor units converted into shares of BGC Group Class B common stock due to the Corporate Conversion (in shares)	1.8	20.5
Common stock, shares issued for exchange of units (in shares)		13.6
Number of shares repurchased (in shares)		24.2
Restricted Shares
Class of Stock [Line Items]
Shares withheld to satisfy tax liabilities (in shares)	4.6
Share-based payment arrangement, decrease for tax withholding obligation	$ 38,400	$ 5,000
Shares withheld for tax withholding obligation (dollars per share)	$ 8.35
Limited Partnership
Class of Stock [Line Items]
Redeemed limited partnership units (in shares)		0.3
Aggregate redemption price of limited partnership units		$ 1,400
Weighted-average price for redemption of limited partnership units (in dollars per shares)		$ 4.71
Cantor units converted into shares of BGC Group Class B common stock due to the Corporate Conversion (in shares)	1.8	0.4
Other Ownership Interest
Class of Stock [Line Items]
Redeemed limited partnership units (in shares)		0.2
Aggregate redemption price of limited partnership units		$ 800
Weighted-average price for redemption of limited partnership units (in dollars per shares)		$ 5.11