XML 59 R47.htm IDEA: XBRL DOCUMENT
v3.7.0.1

Stockholders' and Mezzanine Equity - Dividends Paid (Detail) - $ / shares | 3 Months Ended
--- | ---
Mar. 31, 2017 | Mar. 31, 2016
Common Stock |  |
Dividends Payable [Line Items] |  |
Common Stock, dividends paid per share | $ 0.375 | $ 0.375
Senior Common Stock |  |
Dividends Payable [Line Items] |  |
Common Stock, dividends paid per share | 0.2625 | 0.2625
Series A Preferred Stock |  |
Dividends Payable [Line Items] |  |
Preferred Stock, dividends paid per share | 0.4843749 | 0.4843749
Series B Preferred Stock |  |
Dividends Payable [Line Items] |  |
Preferred Stock, dividends paid per share | 0.4688 | 0.4688
Series C Preferred Stock |  |
Dividends Payable [Line Items] |  |
Preferred Stock, dividends paid per share | 0 | 0.4453
Series D Preferred Stock |  |
Dividends Payable [Line Items] |  |
Preferred Stock, dividends paid per share | $ 0.4375 | $ 0

X
- Definition Aggregate dividends paid during the period for each share of common stock outstanding. + References Reference 1: 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_CommonStockDividendsPerShareCashPaid
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
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 Aggregate dividends paid during the period for each share of preferred stock outstanding. + References No definition available. + Details
Name: | us-gaap_PreferredStockDividendsPerShareCashPaid
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=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_SeriesCPreferredStockMember
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: |