Consolidated Statements of Changes in Equity - USD ($) $ in Thousands	Total	Cantor	Smith Mack	Additional Paid-in Capital	Additional Paid-in Capital Cantor	Additional Paid-in Capital Smith Mack	Treasury Stock	Retained Deficit	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interest in Subsidiaries	Noncontrolling Interest in Subsidiaries Cantor	Noncontrolling Interest in Subsidiaries Smith Mack	Class A Common Stock Common Stock	Class A Common Stock Common Stock Smith Mack	Class B Common Stock	Class B Common Stock Common Stock	Class B Common Stock Additional Paid-in Capital	Class B Common Stock Noncontrolling Interest in Subsidiaries
Beginning balance at Dec. 31, 2020	$ 811,297			$ 2,375,113			$ (315,313)	$ (1,280,828)	$ (28,930)	$ 57,061			$ 3,735			$ 459
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss) available to common stockholders	153,488							124,007		29,481
Other comprehensive gain, net of tax	(13,446)								(11,618)	(1,828)
Equity-based compensation	17,924			13,015						4,887			22
Dividends to common stockholders	(15,098)							(15,098)		0
Earnings distributions to limited partnership interests and other noncontrolling interests	(22,658)									(22,658)
Grant of exchangeability and redemption of limited partnership interests	119,959		$ 1,160	69,855		$ 9,825				49,524		$ (8,683)	580	$ 18
Issuance of Class A common stock (net of costs)	1,510			1,492						14			4
Redemption of FPUs	(408)									(408)
Repurchase of Class A common stock	(365,398)						(307,773)			(57,625)
Forfeitures of Class A common stock	(553)			181			(648)			(86)
Contributions of capital to and from Cantor for equity-based compensation		$ (28,011)			$ (15,429)						$ (12,582)
Cantor purchase of Cantor units from BGC Holdings upon redemption of FPUs	7,894									7,894
Acquisition of Futures Exchange Group	(9,022)			(7,616)						(1,406)
Other	4,677			4,699						(22)
Ending balance at Dec. 31, 2021	663,315			2,451,135			(623,734)	(1,171,919)	(40,548)	43,563			4,359			459
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss) available to common stockholders	58,867							48,712		10,155
Other comprehensive gain, net of tax	(5,668)								(4,883)	(785)
Equity-based compensation	13,946			10,599						3,314			33
Dividends to common stockholders	(14,859)							(14,859)
Earnings distributions to limited partnership interests and other noncontrolling interests	(7,598)									(7,598)
Grant of exchangeability and redemption of limited partnership interests	122,841			92,245						30,286			310
Issuance of Class A common stock (net of costs)	3,802			3,780						17			5
Redemption of FPUs	(249)									(249)
Repurchase of Class A common stock	(103,888)						(87,507)			(16,381)
Forfeitures of Class A common stock	(262)			(8)			(213)			(41)
Contributions of capital to and from Cantor for equity-based compensation		(2,570)			(1,946)						(624)
Issuance of Class A common stock and RSUs for acquisitions			2,710			2,279						419		12
Cantor purchase of Cantor units from BGC Holdings upon redemption of FPUs	1,487									1,487
Other	1,334			1,334
Ending balance at Dec. 31, 2022	733,208			2,559,418			(711,454)	(1,138,066)	(45,431)	63,563			4,719			459
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss) available to common stockholders	38,775							36,265		2,510
Other comprehensive gain, net of tax	7,607								6,849	758
Equity-based compensation	126,738			124,825			8			1,766			139
Dividends to common stockholders	(17,381)							(17,381)
Earnings distributions to limited partnership interests and other noncontrolling interests	(28,946)			(16,652)						(12,294)
Grant of exchangeability and redemption of limited partnership interests	113,201			86,505						26,405			291
Issuance of Class A common stock (net of costs)	214			195						14			5
Redemption of FPUs	(702)			(155)						(547)
Repurchase of Class A common stock	(114,580)						(107,889)			(6,691)
Forfeitures of Class A common stock	(1,190)			331			(1,410)			(111)
Contributions of capital to and from Cantor for equity-based compensation		$ 2,782			$ 2,666						$ 116
Issuance of Class A common stock and RSUs for acquisitions			$ 7,275			$ 6,843						$ 377		$ 55
Cantor purchase of Cantor units from BGC Holdings upon redemption of FPUs	11,539									11,539
Redemption of FPUs and issuance of RSUs due to the Corporate Conversion	14,506			12,410						2,096
Cantor units converted into shares of BGC Group Class B common stock due to the Corporate Conversion, 63,974,374 shares															$ 0	640	$ 75,788	$ (76,428)
Restricted stock awards granted upon conversion of limited partnership interests due to the Corporate Conversion, 38,610,233 shares	0			(386)									386
Conversion of Class B common stock to Class A common stock, 405,801 shares	0												4			(4)
Other	5,110			5,110						0
Ending balance at Dec. 31, 2023	$ 898,156			$ 2,105,130			$ (67,414)	$ (1,119,182)	$ (38,582)	$ 13,073			$ 4,036			$ 1,095