Compensation - Activity Associated with Limited Partnership Units Awarded to BGC Employees (Detail) - LPUs - shares shares in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of units, redeemed (in shares)	29,959	24,079	17,782
BGC Holdings LPUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of units, redeemed (in shares)	29,363	23,001	16,618
Newmark Holdings LPUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of units, redeemed (in shares)	596	1,078	1,164