XML 86 R70.htm IDEA: XBRL DOCUMENT
v3.20.4

Prior Period Financial Statement Revisions - Summary of Revision of Consolidated Statements of Changes in Equity (Details) (Parenthetical) - shares | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Class A Common Stock [Member] |  |  |
Error Corrections And Prior Period Adjustments Restatement [Line Items] |  |  |
Grant of exchangeability and redemption of limited partnership interests, shares | 13,190,311 | 15,008,431 | 18,287,721

X
- Definition Number of shares issued during the period related to redemptions and exchanges of limited partnership interests. + References No definition available. + Details
Name: | bgcp_CommonStockIssuedRelatedToRedemptionsAndExchangesOfLimitedPartnershipInterests
Namespace Prefix: | bgcp_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_ErrorCorrectionsAndPriorPeriodAdjustmentsRestatementLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_StatementClassOfStockAxis=us-gaap_CommonClassAMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |