Compensation - Additional Information (Detail) $ in Thousands			12 Months Ended
	Jul. 01, 2023 USD ($) shares	Jun. 30, 2023 USD ($) shares	Dec. 31, 2024 USD ($) shares	Dec. 31, 2023 USD ($) shares	Dec. 31, 2022 USD ($) shares	Dec. 31, 2021 shares	Nov. 22, 2021 shares	Nov. 21, 2021 shares	Jul. 01, 2021 shares	Jun. 05, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate number of shares grant of future awards (in shares)			440,800,000
Restricted stock awards (in shares)			0	38,610,233
Restricted stock awards granted upon conversion of limited partnership interests due to the Corporate Conversion | $				$ 0
Limited partnership interest, conversion ratio			1							1
Number of share-equivalent limited partnership units exchangeable into shares (in shares)			0	0
Number of restricted stock unit settled per common stock (in shares)			1
Aggregate estimated fair value of limited partnership units and restricted stock units | $			$ 14,700	$ 7,400
Aggregate estimated fair value of the deferred compensation awards | $			$ 0	$ 600
Shares, forfeited (in shares)			300,000	1,400,000
Number of shares released the restrictions (in shares)			0	2,300,000
Shares withheld to satisfy tax liabilities (in shares)				1,000,000.0
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock awards (in shares)	25,300,000	22,500,000
Fair value amount of shares granted | $			$ 176,141	$ 283,418	$ 30,406
Share-based payment arrangement, decrease for tax withholding obligation | $	$ 74,000	$ 49,200
Unrecognized compensation expense related to unvested | $			$ 230,100	$ 161,000
Unrecognized compensation expense related to unvested recognized period			4 years 6 months 29 days	5 years 11 months 15 days
Weighted- Average Remaining Contractual Term (Years)			4 years 6 months 29 days	5 years 11 months 15 days	2 years 5 months 1 day	2 years 3 months 7 days
Limited partnership units outstanding (in shares)			72,498,000	64,942,000	12,046,000	11,034,000
Number of Units, Granted (in shares)			22,533,000	68,732,000	7,125,000
Restricted Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock awards (in shares)	38,600,000
Fair value amount of shares granted | $			$ 0	$ 168,716
Unrecognized compensation expense related to unvested | $			$ 5,800	$ 49,900
Weighted- Average Remaining Contractual Term (Years)			7 months 2 days	2 years 6 months 18 days
Equity-based compensation expense | $			$ 57,000	$ 24,700
Limited partnership units outstanding (in shares)			7,304,000	27,953,000	0
Number of Units, Granted (in shares)	38,600,000		0	38,610,000
Shares withheld to satisfy tax liabilities (in shares)			4,600,000	1,000,000.0
Accelerated vesting (in shares)			4,500,000
Accelerated cost | $			$ 27,100
Dividend eligible shares (in shares)			600,000
Non-exchangeable LPUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Redemption (in shares)	54,000,000	16,900,000
Non-exchangeable FPUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Redemption (in shares)		5,600,000
Restricted Stock Units, Tax Account
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock awards granted upon conversion of limited partnership interests due to the Corporate Conversion | $		$ 49,200	$ 123,100
Fair value amount of shares granted | $	$ 74,000
Unrecognized compensation expense related to unvested | $			70,000	$ 92,700
Fair value of shares vested | $			$ 17,600	$ 27,700
Weighted- Average Remaining Contractual Term (Years)			7 years 11 months 23 days	8 years 9 months 25 days
Equity-based compensation expense | $			$ 21,600	$ 31,900
Non-exchangeable PSU
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Redemption (in shares)	9,900,000	10,600,000
Restricted BGC Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Limited partnership units outstanding (in shares)			0	100,000
Restricted Stock, Dividend Eligible
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Limited partnership units outstanding (in shares)			22,900,000	26,300,000
Minimum | Restricted Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares vesting period			5 years
Maximum | Restricted Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares vesting period			10 years
LPUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Limited partnership units outstanding (in shares)			0	0	110,348,000	112,115,000
Number of Units, Granted (in shares)			0	9,688,000	27,968,000
LPUs | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted shares, restriction period			2 years
LPUs | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted shares, restriction period			5 years
Newmark
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares released the restrictions (in shares)			0	1,000,000.0
Newmark | Restricted BGC Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Limited partnership units outstanding (in shares)			0	0
Newmark | LPUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Limited partnership units outstanding (in shares)			2,936,000	8,779,000	9,351,000	11,051,000
Number of Units, Granted (in shares)			0	0	0
Newmark | LPUs | REUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Notional value with post-termination pay-out amount | $			$ 500	$ 700
Aggregate estimated fair value of limited partnership units | $			$ 200	$ 300
BGC Holdings | Non-exchangeable PSU
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Redemption (in shares)	16,300,000
BGC Holdings | LPUs | REUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of unvested limited partnership units with post-termination pay-out (in shares)			0
Number of outstanding limited partnership units, unvested (in shares)			100,000	100,000
Class A Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of share-equivalent limited partnership units exchangeable into shares (in shares)			300,000	200,000
Stock issued to employees (in shares)			8,700,000	2,200,000
Share-based payment arrangement, decrease for tax withholding obligation | $			$ 41,000	$ 3,900
Shares, forfeited (in shares)			1,439,575	1,428,363
Class A Common Stock | Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Value of shares withheld | $			$ 27,800	$ 11,500
Class A Common Stock | Newmark
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Redemption (in shares)			4,200,000
Limited partnership interests exchange ratio			92.79%
Redemption of stock, shares issued			3,300,000
Equity-based compensation expense | $			$ 54,400
Equity Plan | Class A Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized to be delivered pursuant to awards granted (in shares)							500,000,000.0	400,000,000.0	600,000,000