XML 66 R40.htm IDEA: XBRL DOCUMENT
v3.20.1

Mortgage Notes Payable and Credit Facility - Additional Information (Detail) |  | 3 Months Ended |  |
--- | --- | --- | --- | ---
Jul. 02, 2019 USD ($) | Mar. 31, 2020 USD ($) mortgage property | Mar. 31, 2019 USD ($) | Dec. 31, 2019 USD ($) | Jul. 01, 2019 USD ($)
Debt Instrument [Line Items] |  |  |  |  |
Number of properties collateralized in mortgage notes payable | property |  | 121 |  |  |
Payments of deferred financing costs |  | $ 382,000 | $ 279,000 |  |
Fair value of mortgage notes payable |  | 501,900,000 |  |  |
Line of credit outstanding |  | $ 20,846,000 |  | $ 51,579,000 |
Weighted average interest rate on debt outstanding (as percent) |  | 4.32% |  |  |
Term loan facility |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Maximum borrowing capacity | $ 160,000,000.0 |  |  |  | $ 75,000,000.0
Revolving credit facility |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Maximum borrowing capacity | $ 100,000,000.0 |  |  |  | $ 85,000,000.0
Line of credit |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Extension fee on initial maturity (as percent) | 0.10% |  |  |  |
Line of credit outstanding |  | $ 181,600,000 |  |  |
Weighted average interest rate (as percent) |  | 2.60% |  |  |
Letters of credit, outstanding |  | $ 12,600,000 |  |  |
Maximum additional amount that can be drawn under Line of Credit |  | $ 17,200,000 |  |  |
Line of credit | Term loan facility |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Term of debt | 5 years |  |  |  |
Line of credit | Revolving credit facility |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Term of debt | 4 years |  |  |  |
Debt instrument fees incurred | $ 1,300,000 |  |  |  |
Letter of credit |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Weighted average interest rate on debt outstanding (as percent) |  | 1.65% |  |  |
Variable rate mortgage loans |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Number of properties collateralized in mortgage notes payable | property |  | 12 |  |  |
Carrying value |  | $ 44,830,000 |  | 45,151,000 |
Mortgage notes payable |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Number of mortgage notes payable | mortgage |  | 58 |  |  |
Number of properties collateralized in mortgage notes payable | property |  | 74 |  |  |
Net book value of collateralized mortgage properties |  | $ 730,500,000 |  |  |
Recourse amount of mortgage notes payable |  | $ 4,800,000 |  |  |
Percentage of debt recourse (as percent) |  | 1.00% |  |  |
Carrying value |  | $ 490,616,000 |  |  |
Weighted average interest rate on debt outstanding (as percent) |  | 3.86% |  |  |
Issued and assumed mortgage notes payable |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Number of mortgage notes payable | mortgage |  | 4 |  |  |
Number of properties collateralized in mortgage notes payable | property |  | 4 |  |  |
Fixed rate mortgage loans |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Number of properties collateralized in mortgage notes payable | property |  | 62 |  |  |
Payments of deferred financing costs |  | $ 400,000 | $ 300,000 |  |
Carrying value |  | $ 445,786,000 |  | $ 412,771,000 |
Minimum | Fixed rate mortgage loans |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Stated interest rate (as percent) |  | 2.80% |  |  |
Minimum | LIBOR | Term loan facility |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Spread on LIBOR (as percent) | 2.50% |  |  |  |
Minimum | LIBOR | Variable rate mortgage loans |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Spread on LIBOR (as percent) |  | 2.00% |  |  |
Maximum | Fixed rate mortgage loans |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Stated interest rate (as percent) |  | 6.63% |  |  |
Maximum | LIBOR | Term loan facility |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Spread on LIBOR (as percent) | 2.75% |  |  |  |
Maximum | LIBOR | Variable rate mortgage loans |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |
Spread on LIBOR (as percent) |  | 2.75% |  |  |

X
- Definition Debt instrument collateral percentage + References No definition available. + Details
Name: | good_DebtInstrumentCollateralPercentage
Namespace Prefix: | good_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line of credit facility percentage of extension fee on initial maturity. + References No definition available. + Details
Name: | good_LineOfCreditFacilityPercentageOfExtensionFeeOnInitialMaturity
Namespace Prefix: | good_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

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 Amount of contractual principal due at origination of mortgage loan within investment in mortgage loan on real estate by entity with substantial portion of business acquiring and holding investment real estate or interest in real estate. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 12 -Paragraph Column F -Subsection 29 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 948 -SubTopic 310 -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-29(Column F)) -URI http://asc.fasb.org/extlink&oid=6589523&loc=d3e617274-123014 + Details
Name: | srt_MortgageLoansOnRealEstateFaceAmountOfMortgages
Namespace Prefix: | srt_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
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 Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (b)(1) -URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6031897-161870 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(16)) -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 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 4: 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(16)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
Name: | us-gaap_DebtInstrumentCarryingAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of assets pledged to secure a debt instrument. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 470 -Section 50 -Paragraph 3 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823 + Details
Name: | us-gaap_DebtInstrumentCollateralAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of the fee that accompanies borrowing money under the debt instrument. + 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(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_DebtInstrumentFeeAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
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 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 Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
Name: | us-gaap_DebtInstrumentTerm
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
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
- Definition The total amount of the contingent obligation under letters of credit outstanding as of the reporting date. + References No definition available. + Details
Name: | us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the 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)) -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 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 3: 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(16)) -URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910 + Details
Name: | us-gaap_LineOfCredit
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The effective interest rate at the end of the reporting 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 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_LineOfCreditFacilityInterestRateAtPeriodEnd
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the 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_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding). + 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_LineOfCreditFacilityRemainingBorrowingCapacity
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Fair value portion of notes payable. + 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 210.5-02.19,20,22) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_NotesPayableFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The cash outflow for loan and debt issuance costs. + 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 -URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3291-108585 + Details
Name: | us-gaap_PaymentsOfFinancingCosts
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=good_TermLoanFacilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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

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

X
- Details
Name: | us-gaap_DebtInstrumentAxis=good_NewMortgageNotesPayableMember
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: | us-gaap_VariableRateAxis=us-gaap_LondonInterbankOfferedRateLIBORMember
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: |