XML 73 R50.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Real Estate Dispositions, Held for Sale, and Impairment Charges - Components of Income from Real Estate and Related Assets Held for Sale (Detail) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Real Estate Held for Sale |  |  |
Real Estate Properties [Line Items] |  |  |
Operating revenue | $ 1,007 | $ 416 | $ 0
Operating expense | 1,004 | 471 | 0
Other income, net | (334) | (142) | 0
(Expense) income from real estate and related assets sold | (331) | (197) | 0
Assets disposed of by sale |  |  |
Real Estate Properties [Line Items] |  |  |
Operating revenue | 383 | 1,160 | 1,403
Operating expense | 311 | 3,705 | 1,849
Other income, net | 2,763 | 0 | (158)
(Expense) income from real estate and related assets sold | $ 2,835 | $ (2,545) | $ (604)

X
- Definition Disposal Group, Including Discontinued Operation, Other Income (Expense) + References No definition available. + Details
Name: | good_DisposalGroupIncludingDiscontinuedOperationOtherIncomeExpense
Namespace Prefix: | good_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Income loss from real estate and related assets held for sale. + References No definition available. + Details
Name: | good_IncomeLossFromRealEstateAndRelatedAssetsHeldForSale
Namespace Prefix: | good_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of operating expense attributable to disposal group, including, but not limited to, discontinued operation. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 50 -Paragraph 5B -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109222650&loc=SL51721673-107760 + Details
Name: | us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of revenue attributable to disposal group, including, but not limited to, discontinued operation. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 50 -Paragraph 5B -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109222650&loc=SL51721673-107760 + Details
Name: | us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
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_RealEstatePropertiesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_RealEstatePropertiesAxis=good_RealEstateHeldForSaleMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DisposalGroupClassificationAxis=us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |