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Notes Payable and Other Borrowings - Schedule of Notes Payable, Other and Short-term Borrowings (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Nov. 08, 2024	Aug. 21, 2024	Jun. 10, 2024	Dec. 31, 2023	Oct. 19, 2023	Oct. 06, 2023	May 25, 2023	Jul. 10, 2020	Sep. 27, 2019
Debt Instrument [Line Items]
Stated interest rate							8.00%
Total Notes payable and other borrowings	$ 1,337,540				$ 1,183,506
Deferred financing costs	12,000				6,500
Unsecured senior revolving credit agreement \| Unsecured senior revolving credit agreement
Debt Instrument [Line Items]
Unsecured senior revolving credit agreement	$ 195,831				239,180
BGC Group 3.750% Senior Notes due October 1, 2024
Debt Instrument [Line Items]
Stated interest rate	3.75%						3.75%
Carrying amount of Senior Notes	$ 0				254,814
BGC Partners 3.750% Senior Notes due October 1, 2024
Debt Instrument [Line Items]
Stated interest rate	3.75%									3.75%
Carrying amount of Senior Notes	$ 0				44,383
BGC Group 4.375% Senior Notes due December 15, 2025
Debt Instrument [Line Items]
Stated interest rate	4.375%	4.375%				4.375%	4.375%
Carrying amount of Senior Notes	$ 287,462				286,729
BGC Partners 4.375% Senior Notes due December 15, 2025
Debt Instrument [Line Items]
Stated interest rate	4.375%								4.375%	4.375%
Carrying amount of Senior Notes	$ 11,824				11,800
BGC Group 8.000% Senior Notes due May 25, 2028
Debt Instrument [Line Items]
Stated interest rate	8.00%	8.00%				8.00%	8.00%
Carrying amount of Senior Notes	$ 344,620				343,852
BGC Partners 8.000% Senior Notes due May 25, 2028
Debt Instrument [Line Items]
Stated interest rate	8.00%		8.00%					8.00%
Carrying amount of Senior Notes	$ 2,257				2,748
BGC Group 6.600% Senior Notes due June 10, 2029
Debt Instrument [Line Items]
Stated interest rate	6.60%	6.60%		6.60%		6.60%
Carrying amount of Senior Notes	$ 495,546				$ 0