XML 120 R66.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Equity Equity - Cumulative Offering Costs (Details) - USD ($) $ in Thousands | Sep. 30, 2018 | Dec. 31, 2017 | Dec. 31, 2016
--- | --- | --- | ---
Class of Stock [Line Items] |  |  |
Due from Affiliates | $ (1,128) | $ (686) | $ 0
Contingent Advisor Payment Holdback - Organization and Offering Expenses [Member] |  |  |
Class of Stock [Line Items] |  |  |
Cumulative Offering Costs Private and Public Offerings | 2,806 | 1,698 |
Cumulative Organizational Costs Private and Public Offerings | 510 | 359 |
Organizational and Offering Costs Previously Advanced by Advisor | 1,998 | 1,226 |
Payment of Offering and Organizational Cost | 1,318 | 831 |
Due to Affiliate |  | (999) |
Due from Affiliates |  | (677) |
Organizational and Offering Costs Incurred, Net of Advisor Advances, Net Due | 1,496 | $ 381 |
Costs in Excess of Limit | $ 1,820 |  |

X
- Definition Costs in Excess of Limit + References No definition available. + Details
Name: | gcnl_CostsinExcessofLimit
Namespace Prefix: | gcnl_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Cumulative offering costs private and public offerings. + References No definition available. + Details
Name: | gcnl_CumulativeOfferingCostsPrivateAndPublicOfferings
Namespace Prefix: | gcnl_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Cumulative organizational costs private and public offerings. + References No definition available. + Details
Name: | gcnl_CumulativeOrganizationalCostsPrivateAndPublicOfferings
Namespace Prefix: | gcnl_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Organizational and offering costs previously advanced by the advisor. + References No definition available. + Details
Name: | gcnl_OrganizationalAndOfferingCostsPreviouslyAdvancedByAdvisor
Namespace Prefix: | gcnl_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Organizational and Offering Costs Incurred, Net of Advisor Advances, Net Due + References No definition available. + Details
Name: | gcnl_OrganizationalandOfferingCostsIncurredNetofAdvisorAdvancesNetDue
Namespace Prefix: | gcnl_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Payment of Offering and Organizational Cost + References No definition available. + Details
Name: | gcnl_PaymentofOfferingandOrganizationalCost
Namespace Prefix: | gcnl_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
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_ClassOfStockLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition For an unclassified balance sheet, amount of receivables due from an entity that is affiliated with the reporting entity by means of direct or indirect ownership. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 850 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39599-107864 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(k)(1)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 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 210.7-03.3) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 850 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864 Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 850 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39622-107864 + Details
Name: | us-gaap_DueFromAffiliates
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of payable due to an entity that is affiliated with the reporting entity by means of direct or indirect ownership. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 850 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 946 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.6-04.12(3)) -URI http://asc.fasb.org/extlink&oid=6488278&loc=d3e603758-122996 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.15(3)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(k)(1)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.17) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 852 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=6918054&loc=d3e56071-112765 + Details
Name: | us-gaap_DueToAffiliateCurrentAndNoncurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_RelatedPartyTransactionAxis=gcnl_ContingentAdvisorPaymentHoldbackOrganizationandOfferingExpensesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |