XML 88 R65.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Equity and Mezzanine Equity - Summary of Changes in Stockholders' Equity (Detail) | 1 Months Ended | 12 Months Ended
--- | --- | ---
Feb. 29, 2012 | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Series C Preferred Stock |  |  |  |
Dividends Payable [Line Items] |  |  |  |
Preferred stock, dividend rate (as percent) | 7.125% |  |  |
Ordinary Income | Common Stock and Non-controlling OP Units |  |  |  |
Dividends Payable [Line Items] |  |  |  |
Common stock, dividend rate (as percent) |  | 24.46913% | 39.63189% | 28.81758%
Ordinary Income | Senior Common Stock |  |  |  |
Dividends Payable [Line Items] |  |  |  |
Common stock, dividend rate (as percent) |  | 100.00% | 100.00% | 100.00%
Ordinary Income | Series A Preferred Stock |  |  |  |
Dividends Payable [Line Items] |  |  |  |
Preferred stock, dividend rate (as percent) |  | 100.00% | 100.00% | 100.00%
Ordinary Income | Series B Preferred Stock |  |  |  |
Dividends Payable [Line Items] |  |  |  |
Preferred stock, dividend rate (as percent) |  | 100.00% | 100.00% | 100.00%
Ordinary Income | Series C Preferred Stock |  |  |  |
Dividends Payable [Line Items] |  |  |  |
Preferred stock, dividend rate (as percent) |  | 0.00% | 0.00% | 100.00%
Ordinary Income | Series D Preferred Stock |  |  |  |
Dividends Payable [Line Items] |  |  |  |
Preferred stock, dividend rate (as percent) |  | 100.00% | 100.00% | 100.00%
Return of Capital | Common Stock and Non-controlling OP Units |  |  |  |
Dividends Payable [Line Items] |  |  |  |
Common stock, dividend rate (as percent) |  | 75.53087% | 60.36811% | 71.18242%
Return of Capital | Senior Common Stock |  |  |  |
Dividends Payable [Line Items] |  |  |  |
Common stock, dividend rate (as percent) |  | 0.00% | 0.00% | 0.00%
Return of Capital | Series A Preferred Stock |  |  |  |
Dividends Payable [Line Items] |  |  |  |
Preferred stock, dividend rate (as percent) |  | 0.00% | 0.00% | 0.00%
Return of Capital | Series B Preferred Stock |  |  |  |
Dividends Payable [Line Items] |  |  |  |
Preferred stock, dividend rate (as percent) |  | 0.00% | 0.00% | 0.00%
Return of Capital | Series C Preferred Stock |  |  |  |
Dividends Payable [Line Items] |  |  |  |
Preferred stock, dividend rate (as percent) |  | 0.00% | 0.00% | 0.00%
Return of Capital | Series D Preferred Stock |  |  |  |
Dividends Payable [Line Items] |  |  |  |
Preferred stock, dividend rate (as percent) |  | 0.00% | 0.00% | 0.00%
Long-Term Capital Gains | Common Stock and Non-controlling OP Units |  |  |  |
Dividends Payable [Line Items] |  |  |  |
Common stock, dividend rate (as percent) |  | 0.00% | 0.00% | 0.00%
Long-Term Capital Gains | Senior Common Stock |  |  |  |
Dividends Payable [Line Items] |  |  |  |
Common stock, dividend rate (as percent) |  | 0.00% | 0.00% | 0.00%
Long-Term Capital Gains | Series A Preferred Stock |  |  |  |
Dividends Payable [Line Items] |  |  |  |
Preferred stock, dividend rate (as percent) |  | 0.00% | 0.00% | 0.00%
Long-Term Capital Gains | Series B Preferred Stock |  |  |  |
Dividends Payable [Line Items] |  |  |  |
Preferred stock, dividend rate (as percent) |  | 0.00% | 0.00% | 0.00%
Long-Term Capital Gains | Series C Preferred Stock |  |  |  |
Dividends Payable [Line Items] |  |  |  |
Preferred stock, dividend rate (as percent) |  | 0.00% | 0.00% | 0.00%
Long-Term Capital Gains | Series D Preferred Stock |  |  |  |
Dividends Payable [Line Items] |  |  |  |
Preferred stock, dividend rate (as percent) |  | 0.00% | 0.00% | 0.00%

X
- Definition Common stock dividend rate percentage. + References No definition available. + Details
Name: | good_CommonStockDividendRatePercentage
Namespace Prefix: | good_
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_DividendsPayableLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The percentage rate used to calculate dividend payments on preferred stock. + References No definition available. + Details
Name: | us-gaap_PreferredStockDividendRatePercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

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

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

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

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

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

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

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

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

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