XML 131 R56.htm IDEA: XBRL DOCUMENT
v3.19.3.a.u2

Organization and Basis of Presentation - Additional Information (Detail) $ / shares in Units, $ in Thousands |  |  |  |  |  |  |  | 11 Months Ended | 12 Months Ended |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Nov. 30, 2018 shares | Nov. 23, 2018 USD ($) | Nov. 23, 2018 USD ($) | Nov. 07, 2018 USD ($) | Sep. 05, 2018 USD ($) | Dec. 26, 2017 shares | Dec. 15, 2017 $ / shares shares | Sep. 08, 2017 USD ($) | Nov. 30, 2018 Segment shares | Dec. 31, 2019 USD ($) Segment shares | Dec. 31, 2018 USD ($) shares | Dec. 31, 2017 shares | Jan. 01, 2019 USD ($) | Mar. 19, 2018 USD ($) | Jan. 01, 2018 USD ($)
Description Of Business [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Equity method investments |  |  |  |  |  |  |  |  |  |  | $ 40,000 | $ 35,211 |  |  |  |
Number of reporting segments | Segment |  |  |  |  |  |  |  |  |  | 2 | 1 |  |  |  |  |
Retained deficit |  |  |  |  |  |  |  |  |  |  | $ (1,241,754) | (1,105,019) |  |  |  |
Accumulated other comprehensive income (loss) |  |  |  |  |  |  |  |  |  |  | (33,102) | (24,465) |  |  |  |
Noncontrolling interest in subsidiaries |  |  |  |  |  |  |  |  |  |  | 57,911 | $ 94,801 |  |  |  |
Operating lease, right-of-use asset | [1] |  |  |  |  |  |  |  |  |  | 169,065 |  |  |  |  |
Operating lease, liability | [1] |  |  |  |  |  |  |  |  |  | $ 187,398 |  |  |  |  |
ASU No. 2018-03 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Description Of Business [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Retained deficit |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 2,100
Accumulated other comprehensive income (loss) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 2,900
Noncontrolling interest in subsidiaries |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 800
ASU No. 2018-03 [Member] | Retained Deficit [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Description Of Business [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Tax effect impact for increase or decrease to the liability |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 400
ASU No. 2018-03 [Member] | Accumulated Other Comprehensive Income (Loss) [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Description Of Business [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Tax effect impact for increase or decrease to the liability |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 600
ASU No. 2018-03 [Member] | Noncontrolling Interest in Subsidiaries [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Description Of Business [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Tax effect impact for increase or decrease to the liability |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 200
ASU No. 2016-02 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Description Of Business [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Operating lease, right-of-use asset |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 192,400 |  |
Operating lease, liability |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 206,000 |  |
BGC Holdings Partnership Unit [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Description Of Business [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Exchangeable limited partnership units | shares |  | 1,458,931 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Newmark [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Description Of Business [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Percentage of voting power |  | 94.00% |  |  |  |  |  |  |  | 94.00% |  |  |  |  |  |
Percentage of economics of outstanding common stock |  | 87.00% |  |  |  |  |  |  |  | 87.00% |  |  |  |  |  |
Revolving Credit Agreement [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Description Of Business [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Line of credit facility, borrowing amount |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 150,000 |
Intercompany Credit Agreement [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Description Of Business [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Line of credit facility, borrowing amount |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 150,000 |
8.125% Senior Notes Due 2042 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Description Of Business [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Stated interest rate |  |  |  |  |  | 8.125% |  |  |  |  |  |  |  |  |  |
Debt maturity year |  |  |  |  |  | 2042 |  |  |  |  |  |  |  |  |  |
5.375% Senior Notes Due 2019 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Description Of Business [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Stated interest rate |  |  | 5.375% | 5.375% |  |  |  |  |  |  |  |  |  |  |  |
Debt maturity year |  |  | 2019 |  |  |  |  |  |  |  | 2019 |  |  |  |  |
Repayments of outstanding borrowings |  |  |  | $ 300,000 |  |  |  |  |  |  |  |  |  |  |  |
Class A Common Stock [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Description Of Business [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Issuance of Class A common stock (net of costs), shares | shares |  |  |  |  |  |  |  |  |  |  | 212,711 | 26,003,424 | 1,994,670 |  |  |
Common stock, shares issued | shares |  |  |  |  |  |  |  |  |  |  | 358,440,000 | 341,745,000 |  |  |  |
Class A Common Stock [Member] | Newmark [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Description Of Business [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Stockholders received on per share |  | 0.463895 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Common stock, shares issued | shares |  | 131,886,409 |  |  |  |  |  |  |  | 131,886,409 |  |  |  |  |  |
Class A Common Stock [Member] | Newmark [Member] | Cantor [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Description Of Business [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Common stock, shares issued | shares |  | 449,917 |  |  |  |  |  |  |  | 449,917 |  |  |  |  |  |
Class B Common Stock [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Description Of Business [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Issuance of Class A common stock (net of costs), shares | shares |  |  |  |  |  |  |  |  |  |  | 0 |  |  |  |  |
Common stock, shares issued | shares |  |  |  |  |  |  |  |  |  |  | 45,884,000 | 45,884,000 |  |  |  |
Class B Common Stock [Member] | Newmark [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Description Of Business [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Stockholders received on per share |  | 0.463895 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Common stock, shares issued | shares |  | 21,285,537 |  |  |  |  |  |  |  | 21,285,537 |  |  |  |  |  |
Exchange ratio |  | 0.9400 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Real Estate L.P. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Description Of Business [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Equity method investments |  |  |  |  |  |  |  |  | $ 100,000 |  |  |  |  |  |  |
BPF [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Description Of Business [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Business acquisition date |  |  |  |  |  |  |  |  | Jul. 17, 2017 |  |  |  |  |  |  |
Business acquisition effective date |  |  |  |  |  |  |  |  | Sep. 08, 2017 |  |  |  |  |  |  |
Newmark [Member] | Intercompany Credit Agreement [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Description Of Business [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Repayments of outstanding borrowings |  |  |  |  | $ 150,000 |  |  |  |  |  |  |  |  |  |  |
Newmark [Member] | 8.125% Senior Notes Due 2042 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Description Of Business [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Repayments of outstanding borrowings |  |  |  |  |  | $ 112,500 |  |  |  |  |  |  |  |  |  |
Newmark [Member] | 5.375% Senior Notes Due 2019 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Description Of Business [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Repayments of outstanding borrowings |  |  | $ 300,000 |  |  |  |  |  |  |  |  |  |  |  |  |
Newmark [Member] | IPO [Member] | Class A Common Stock [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Description Of Business [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Issuance of Class A common stock (net of costs), shares | shares |  |  |  |  |  |  |  | 20,000,000 |  |  |  |  |  |  |  |
Closing price per share | $ / shares |  |  |  |  |  |  |  | $ 14.00 |  |  |  |  |  |  |  |
Options to purchase additional shares of common stock period |  |  |  |  |  |  |  | 30 days |  |  |  |  |  |  |  |
Option to purchase additional shares | shares |  |  |  |  |  |  | 3,000,000 |  |  |  |  |  |  |  |  |
[1] | As of December 31, 2019, $169.1 million and $187.4 million, relating to lease ROU assets and lease liabilities, respectively, is attributable to the adoption of ASU No. 2016-02, Leases (Topic 842). See Note 25—“Leases”, in addition to the information under the heading “Recently Adopted Accounting Pronouncements” included in Note 1—“Organization and Basis of Presentation” for additional information.

X
- Definition Common shares distributed to stockholders per share. + References No definition available. + Details
Name: | bgcp_CommonSharesDistributedToStockholdersPerShare
Namespace Prefix: | bgcp_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | duration

X
- Definition Year when the debt instrument is scheduled to be fully repaid. + References No definition available. + Details
Name: | bgcp_DebtInstrumentMaturityYear
Namespace Prefix: | bgcp_
Data Type: | xbrli:gYearItemType
Balance Type: | na
Period Type: | duration

X
- Definition Description Of Business [Line Items] + References No definition available. + Details
Name: | bgcp_DescriptionOfBusinessLineItems
Namespace Prefix: | bgcp_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of units purchase by related party in operating partnership as limited partner. + References No definition available. + Details
Name: | bgcp_NumberOfUnitsPurchaseByRelatedPartyInOperatingPartnershipAsLimitedPartner
Namespace Prefix: | bgcp_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Options to purchase additional shares of common stock period. + References No definition available. + Details
Name: | bgcp_OptionsToPurchaseAdditionalSharesOfCommonStockPeriod
Namespace Prefix: | bgcp_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of economics of outstanding common stock upon the distribution. + References No definition available. + Details
Name: | bgcp_PercentageOfEconomicsOfOutstandingCommonStockUponDistribution
Namespace Prefix: | bgcp_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percentage of voting interest upon the distribution. + References No definition available. + Details
Name: | bgcp_PercentageOfVotingInterestUponDistribution
Namespace Prefix: | bgcp_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Stockholders distribution current exchange ratio. + References No definition available. + Details
Name: | bgcp_StockholdersDistributionCurrentExchangeRatio
Namespace Prefix: | bgcp_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Underwriter overallotment option to purchase common stock number. + References No definition available. + Details
Name: | bgcp_UnderwriterOverallotmentOptionToPurchaseCommonStockNumber
Namespace Prefix: | bgcp_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=118930883&loc=d3e637-108580 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 14A -URI http://asc.fasb.org/extlink&oid=118930883&loc=SL7669686-108580 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 14 -URI http://asc.fasb.org/extlink&oid=118930883&loc=d3e681-108580 + Details
Name: | us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Date when the business acquisition agreement was executed, in CCYY-MM-DD format. + References No definition available. + Details
Name: | us-gaap_BusinessAcquisitionDateOfAcquisitionAgreement1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

X
- Definition Date when the acquirer obtains control of the acquiree, in CCYY-MM-DD format. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 25 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=116868678&loc=d3e848-128460 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 25 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=116868678&loc=d3e845-128460 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463 + Details
Name: | us-gaap_BusinessAcquisitionEffectiveDateOfAcquisition1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

X
- Definition Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_CommonStockSharesIssued
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Contractual interest rate for funds borrowed, under the debt agreement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 323 -SubTopic 10 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=109237563&loc=d3e33749-111570 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 25 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=115929826&loc=d3e8813-108599 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.12) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_EquityMethodInvestments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which is directly or indirectly attributable to that ownership interest in subsidiary equity which is not attributable to the parent (that is, noncontrolling interest, previously referred to as minority interest). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(24)) -URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.31) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(22)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
Name: | us-gaap_MinorityInterest
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of cumulative effect of the change in accounting principle or new accounting pronouncement on retained earnings or other components of equity or net assets in the statement of financial position as of the beginning of the earliest period presented. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 250 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b)(3) -URI http://asc.fasb.org/extlink&oid=109234566&loc=d3e22499-107794 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 250 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=109234566&loc=d3e22583-107794 + Details
Name: | us-gaap_NewAccountingPronouncementOrChangeInAccountingPrincipleCumulativeEffectOfChangeOnEquityOrNetAssets1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements. + References No definition available. + Details
Name: | us-gaap_NumberOfReportableSegments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Present value of lessee's discounted obligation for lease payments from operating lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=77888419&loc=SL77918627-209977 + Details
Name: | us-gaap_OperatingLeaseLiability
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of lessee's right to use underlying asset under operating lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 1 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=77888419&loc=SL77918627-209977 + Details
Name: | us-gaap_OperatingLeaseRightOfUseAsset
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 15 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3291-108585 + Details
Name: | us-gaap_RepaymentsOfLongTermDebt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The cumulative amount of the reporting entity's undistributed earnings or deficit. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(30)(a)(3)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(23)(a)(4)) -URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770 + Details
Name: | us-gaap_RetainedEarningsAccumulatedDeficit
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Per share amount received by subsidiary or equity investee for each share of common stock issued or sold in the stock transaction. + References No definition available. + Details
Name: | us-gaap_SaleOfStockPricePerShare
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of new stock issued during the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(28)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_StockIssuedDuringPeriodSharesNewIssues
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_AdjustmentsForNewAccountingPronouncementsAxis=us-gaap_AccountingStandardsUpdate201803Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=us-gaap_RetainedEarningsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=us-gaap_AccumulatedOtherComprehensiveIncomeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=us-gaap_NoncontrollingInterestMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AdjustmentsForNewAccountingPronouncementsAxis=us-gaap_AccountingStandardsUpdate201602Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PartnerTypeOfPartnersCapitalAccountAxis=bgcp_BGCHoldingsPartnershipUnitsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=bgcp_NewmarkMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CreditFacilityAxis=bgcp_RevolvingCreditAgreementMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CreditFacilityAxis=bgcp_IntercompanyCreditAgreementMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=bgcp_EightPointOneTwoFivePercentSeniorNotesDueTwoThousandFortyTwoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=bgcp_FivePointThreeSevenFivePercentSeniorNotesDueTwoThousandNineteenMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=bgcp_CantorMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=bgcp_CFRealEstateFinanceHoldingsLimitedPartnershipMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=bgcp_BerkeleyPointFinancialLLCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=bgcp_NewmarkMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SubsidiarySaleOfStockAxis=us-gaap_IPOMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |