XML 69 R53.htm IDEA: XBRL DOCUMENT
v3.20.2

Divestitures - Additional Information (Detail) - USD ($) | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2020 | Jun. 30, 2019 | Mar. 31, 2019 | Jun. 30, 2020 | Jun. 30, 2019
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items] |  |  |  |  |
Gain (loss) on divestitures and sale of investments |  | $ (1,619,000) |  |  | $ 18,435,000
Other Sales [Member] |  |  |  |  |
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items] |  |  |  |  |
Gain (loss) on divestitures and sale of investments | $ 0 |  | $ 18,400,000 | $ 0 |

X
- Definition The aggregate of gain (loss) from a divestiture or sale of a business activity, and the gain (loss) on the sale of an investment. + References No definition available. + Details
Name: | bgcp_GainLossOnDivestitureAndOrSaleOfInvestment
Namespace Prefix: | bgcp_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
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_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=bgcp_OtherSalesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |