Compensation - Summary of the BGC Holdings and Newmark Holdings LPUs held by BGC Employees (Detail) - LPUs - shares	Mar. 31, 2023	Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Balance outstanding (in shares)	103,926,000	110,348,000
Newmark
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Balance outstanding (in shares)	9,248,000	9,351,000
Regular Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Balance outstanding (in shares)	73,543,000
Regular Units | Newmark
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Balance outstanding (in shares)	7,081,000
Preferred Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Balance outstanding (in shares)	30,383,000
Preferred Units | Newmark
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Balance outstanding (in shares)	2,167,000