Compensation - Summary of the BGC Holdings and Newmark Holdings LPUs held by BGC Employees (Detail) - LPUs - shares	Sep. 30, 2022	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Balance outstanding (in shares)	109,503,000	112,115,000
Newmark
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Balance outstanding (in shares)	10,273,000	11,051,000
Regular Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Balance outstanding (in shares)	77,126,000
Regular Units | Newmark
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Balance outstanding (in shares)	7,841,000
Preferred Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Balance outstanding (in shares)	32,377,000
Preferred Units | Newmark
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Balance outstanding (in shares)	2,432,000