XML 53 R39.htm IDEA: XBRL DOCUMENT
v3.20.1

Mortgage Notes Payable and Credit Facility - Company's Mortgage Notes Payable and Line of Credit Additional Information (Detail) | 3 Months Ended
--- | ---
Mar. 31, 2020 mortgage property
Debt Instrument [Line Items] |
Weighted average interest rate on debt outstanding (as percent) | 4.32%
Encumbered properties | 121
LIBOR |
Debt Instrument [Line Items] |
Variable rate at period end (as percent) | 0.99%
Fixed rate mortgage loans |
Debt Instrument [Line Items] |
Encumbered properties | 62
Fixed rate mortgage loans | Minimum |
Debt Instrument [Line Items] |
Stated interest rate (as percent) | 2.80%
Fixed rate mortgage loans | Maximum |
Debt Instrument [Line Items] |
Stated interest rate (as percent) | 6.63%
Mortgage notes payable |
Debt Instrument [Line Items] |
Number of mortgage notes payable | mortgage | 58
Maturity date of mortgage notes payable, start date | Jul. 01, 2020
Maturity date of mortgage notes payable, end date | Aug. 01, 2037
Weighted average interest rate on debt outstanding (as percent) | 3.86%
Encumbered properties | 74
Variable rate mortgage loans |
Debt Instrument [Line Items] |
Encumbered properties | 12
Variable rate mortgage loans | Minimum | LIBOR |
Debt Instrument [Line Items] |
Spread on LIBOR (as percent) | 2.00%
Variable rate mortgage loans | Maximum | LIBOR |
Debt Instrument [Line Items] |
Spread on LIBOR (as percent) | 2.75%
Variable rate revolving credit facility | Revolving credit facility |
Debt Instrument [Line Items] |
Encumbered properties | 47
Variable rate revolving credit facility | LIBOR | Revolving credit facility |
Debt Instrument [Line Items] |
Spread on LIBOR (as percent) | 1.65%

X
- Definition Debt Instrument, Interest Rate, Variable Rate at Period End + References No definition available. + Details
Name: | good_DebtInstrumentInterestRateVariableRateatPeriodEnd
Namespace Prefix: | good_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of existing encumbered properties. + References No definition available. + Details
Name: | good_NumberOfExistingEncumberedProperties
Namespace Prefix: | good_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of mortgage notes payable. + References No definition available. + Details
Name: | good_NumberOfMortgageNotesPayable
Namespace Prefix: | good_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percentage points added to the reference rate to compute the variable rate on the debt instrument. + References No definition available. + Details
Name: | us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

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 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_DebtInstrumentLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Latest date the outstanding debt instruments are required to be repaid, in CCYY-MM-DD format. + 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)(2)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_DebtInstrumentMaturityDateRangeEnd1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

X
- Definition Earliest date the outstanding debt instruments are required to be repaid, in CCYY-MM-DD format. + 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)(2)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_DebtInstrumentMaturityDateRangeStart1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

X
- Definition Weighted average interest rate of debt outstanding. + References No definition available. + Details
Name: | us-gaap_DebtWeightedAverageInterestRate
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_VariableRateAxis=us-gaap_LondonInterbankOfferedRateLIBORMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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

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

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