XML 81 R68.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Stock Transactions and Unit Redemptions - Additional Information (Detail) - USD ($) |  |  | 1 Months Ended | 3 Months Ended | 12 Months Ended |
--- | --- | --- | --- | --- | --- | ---
Mar. 09, 2018 | Apr. 12, 2017 | May 01, 2018 | Mar. 31, 2018 | Mar. 31, 2017 | Dec. 31, 2017 | Feb. 07, 2017
Class of Stock [Line Items] |  |  |  |  |  |  |
Payment percentage of the gross proceeds from the sale of shares |  | 2.00% |  |  |  |  |
Stock repurchase program and unit redemption remaining authorized amount |  |  |  | $ 172,167,800 |  |  |
Redemptions, Number of Units |  |  |  | 1,723,654 |  |  |
Class B Common Stock [Member] |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |
Common stock, issued during the period |  |  |  | 0 | 0 |  |
Common stock outstanding |  |  |  | 34,848,107 | 34,848,107 | 34,848,000 |
Common stock, shares issued |  |  |  | 34,848,000 |  | 34,848,000 |
Common stock value issued |  |  |  | $ 348,000 |  | $ 348,000 |
Class A Common Stock [Member] |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |
Common stock, issued during the period |  |  |  | 18,925,702 |  | 1,994,670 |
Common stock outstanding |  |  |  | 279,279,000 |  | 256,968,000 |
Common stock, shares issued |  |  |  | 328,529,000 |  | 306,218,000 |
Common stock value issued |  |  |  | $ 3,286,000 |  | $ 3,063,000 |
Company's repurchase and additional redemption authority amount |  |  |  |  |  |  | $ 300,000,000
Stock repurchase program and unit redemption remaining authorized amount |  |  |  | $ 172,200,000 |  |  |
Class A Common Stock [Member] | April 2017 Sales Agreement |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |
Maximum number of shares under the controlled equity offering |  | 20,000,000 |  |  |  |  |
Class A Common Stock [Member] | Controlled Equity Offerings [Member] |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |
Common stock, issued during the period |  |  | 3,200,000 |  |  |  |
Common stock, shares issued |  |  |  | 20,000,000 |  |  |
Redemptions, Number of Units |  |  |  | 1,700,000 |  |  |
Class A Common Stock [Member] | March 2019 Sales Agreement |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |
Maximum number of shares under the controlled equity offering | 300,000,000 |  |  |  |  |  |
Class A Common Stock [Member] | New Controlled Equity Offerings [Member] |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |
Common stock, shares issued |  |  |  | 2,653,971 |  |  |
Common stock value issued |  |  |  | $ 37,100 |  |  |

X
- Definition Maximum number of shares of class A common stock that may be sold under the controlled equity offering sales agreements. + References No definition available. + Details
Name: | bgcp_MaximumAmountOfCommonStockOfferAndSale
Namespace Prefix: | bgcp_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of units redeemed. + References No definition available. + Details
Name: | bgcp_NumberOfUnitsRedeemed
Namespace Prefix: | bgcp_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Commission paid to related party broker for sale of shares. + References No definition available. + Details
Name: | bgcp_PaymentSpecifiedPercentageOfGrossProceedsFromSaleOfShares
Namespace Prefix: | bgcp_
Data Type: | num:percentItemType
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_ClassOfStockLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
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://www.xbrl.org/2003/role/presentationRef -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 Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -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://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=84159872&loc=d3e21463-112644 + Details
Name: | us-gaap_CommonStockSharesOutstanding
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Aggregate par or stated value of issued nonredeemable common stock (or common stock redeemable solely at the option of the issuer). This item includes treasury stock repurchased by the entity. Note: elements for number of nonredeemable common shares, par value and other disclosure concepts are in another section within stockholders' equity. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -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_CommonStockValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Number of new stock issued during the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -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://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=84159872&loc=d3e21463-112644 Reference 3: http://www.xbrl.org/2003/role/presentationRef -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 Reference 4: http://www.xbrl.org/2003/role/presentationRef -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_StockIssuedDuringPeriodSharesNewIssues
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of stock repurchase plan authorized. + References No definition available. + Details
Name: | us-gaap_StockRepurchaseProgramAuthorizedAmount1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount remaining of a stock repurchase plan authorized. + References No definition available. + Details
Name: | us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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

X
- Details
Name: | us-gaap_RelatedPartyTransactionAxis=bgcp_ControlledEquityOfferingsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RelatedPartyTransactionAxis=bgcp_SalesAgreementMarchTwoThousandEighteenMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RelatedPartyTransactionAxis=bgcp_NewControlledEquityOfferingsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |