Compensation - Additional Information (Detail) $ in Thousands			1 Months Ended	12 Months Ended
	Jul. 01, 2023 USD ($) shares	Jun. 30, 2023 USD ($) shares	Oct. 31, 2023 shares	Dec. 31, 2023 USD ($) shares	Dec. 31, 2022 USD ($) shares	Dec. 31, 2021 USD ($) shares	Dec. 31, 2020 shares	Nov. 22, 2021 shares	Nov. 21, 2021 shares	Jul. 01, 2021 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate number of shares grant of future awards (in shares)				477,100,000
Restricted stock awards				38,610,233	0
Restricted stock awards granted upon conversion of limited partnership interests due to the Corporate Conversion, 38,610,233 shares | $				$ 0
Limited partnership interest, conversion ratio				1
Number of share-equivalent limited partnership units exchangeable into shares (in shares)					1,200,000
Number of restricted stock unit settled per common stock (in shares)				1
Aggregate estimated fair value of limited partnership units and restricted stock units | $				$ 7,400	$ 5,900
Aggregate estimated fair value of the deferred compensation awards | $				$ 600	$ 23,900
Shares, forfeited (in shares)				1,400,000	100,000
Number of shares released the restrictions (in shares)				2,300,000	300,000
Deferred cash compensation expense recognized | $				$ 54	$ (542)	$ 347
Shares withheld to satisfy tax liabilities (in shares)			1,000,000
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock awards	25,300,000	22,500,000
Fair value of shares granted | $				283,418	$ 30,406	$ 26,716
Unrecognized compensation expense related to unvested | $				$ 161,000
Unrecognized compensation expense related to unvested recognized period				5 years 11 months 15 days
Limited partnership units outstanding (in shares)				64,942,000	12,046,000	11,034,000	8,960,000
Weighted- Average Remaining Contractual Term (Years)				5 years 11 months 15 days	2 years 5 months 1 day	2 years 3 months 7 days	2 years 5 months 15 days
Number of Units, Granted (in shares)				68,732,000	7,125,000	6,319,000
Restricted Stock Units (RSUs) | Eligible
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Limited partnership units outstanding (in shares)				26,300,000
Restricted Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock awards	38,600,000
Fair value of shares granted | $				$ 168,716
Unrecognized compensation expense related to unvested | $				$ 49,900
Limited partnership units outstanding (in shares)				27,953,000	0
Weighted- Average Remaining Contractual Term (Years)				2 years 6 months 18 days
Equity-based compensation expense | $				$ 24,700
Number of Units, Granted (in shares)	38,600,000			38,610,000
Restricted Shares | Eligible
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Limited partnership units outstanding (in shares)				5,800,000
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, 38,610,233 shares | $		$ 49,200		$ 123,100
Fair value of shares granted | $	$ 74,000
Unrecognized compensation expense related to unvested | $				$ 92,700
Weighted- Average Remaining Contractual Term (Years)				8 years 9 months 25 days
Equity-based compensation expense | $				$ 31,900
Fair value of shares vested | $				$ 27,700
Shares withheld to satisfy tax liabilities (in shares)				1,000,000
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)				100,000	2,300,000
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	110,348,000	112,115,000	137,652,000
Number of Units, Granted (in shares)				9,688,000	27,968,000	34,093,000
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)				1,000,000	100,000
Newmark | Restricted Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Limited partnership units outstanding (in shares)				0	1,100,000
Newmark | LPUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Limited partnership units outstanding (in shares)				8,779,000	9,351,000	11,051,000	13,202,000
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 | $				$ 700	$ 700
Aggregate estimated fair value of limited partnership units | $				$ 300	$ 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	800,000
Notional value with post-termination pay-out amount | $					$ 8,600
Aggregate estimated fair value of limited partnership units | $					$ 3,900
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)				200,000
Shares, forfeited (in shares)				1,428,000	67,000
Class A Common Stock | Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Value of shares withheld | $				$ 11,500	$ 6,600
Class A Common Stock | Newmark
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Limited partnership interests exchange ratio				92.31%
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	400,000,000	600,000,000