| Cover | Jun. 30, 2022 |
| Cover [Abstract] | |
| Document Type | 8-K/A |
| Document Period End Date | Jun. 30, 2022 |
| Entity Registrant Name | BGC Partners, Inc. |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 0-28191 |
| Entity Tax Identification Number | 13-4063515 |
| Entity Address, Address Line One | 499 Park Avenue |
| Entity Address, City or Town | New York |
| Entity Address, State or Province | NY |
| Entity Address, Postal Zip Code | 10022 |
| City Area Code | 212 |
| Local Phone Number | 610-2200 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(g) Security | Class A Common Stock, $0.01 par value |
| Trading Symbol | BGCP |
| Security Exchange Name | NASDAQ |
| Amendment Flag | false |
| Entity Central Index Key | 0001094831 |
| Entity Emerging Growth Company | false |
