Debt Instrument, Extended Term

No definition available.

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- Definition

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

+ Details

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Period Type:	instant

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

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Period Type:	duration

- 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

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 6
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6036836-161870

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399

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-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

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- 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

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Balance Type:	na
Period Type:	instant

- 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

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

- 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

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of unamortized debt discount (premium) and debt issuance costs.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Weighted average interest rate of debt outstanding.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ 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)(3)
-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(a)(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 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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-Name Accounting Standards Codification
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-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Namespace Prefix:	us-gaap_
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Balance Type:	credit
Period Type:	instant

- Details

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- Details

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- Details

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- Details

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- Details

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- Details

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- Details

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- Details

Name:	us-gaap_DebtInstrumentAxis=gcnl_UnsecuredRevolverCreditFacilityMember
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- Details

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Debt - Schedule of Debt (Details) - USD ($)			6 Months Ended
Debt - Schedule of Debt (Details) - USD ($)	Apr. 30, 2019	Jul. 20, 2015	Jun. 30, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Total principal			$ 1,946,836,000	$ 1,362,179,000
Unamortized Deferred Financing Costs and Discounts, net			(11,247,000)	(8,648,000)
Debt, net			1,935,589,000	1,353,531,000
Derivative notional amount			850,000,000	850,000,000
Interest Rate Swap
Debt Instrument [Line Items]
Derivative notional amount			$ 425,000,000
Weighted average interest rate			3.89%
LIBOR
Debt Instrument [Line Items]
Effective interest rate (percent)			2.43%
Mortgages
Debt Instrument [Line Items]
Total principal			$ 1,020,897,000	647,179,000
HealthSpring Mortgage Loan \| Mortgages
Debt Instrument [Line Items]
Total principal			$ 20,972,000	21,219,000
Contractual stated interest rate (percent)			4.175%
Effective interest rate (percent)			4.61%
Midland Mortgage Loan \| Mortgages
Debt Instrument [Line Items]
Total principal			$ 101,266,000	102,262,000
Contractual stated interest rate (percent)			3.94%
Effective interest rate (percent)			4.11%
Emporia Partners Mortgage Loan \| Mortgages
Debt Instrument [Line Items]
Total principal			$ 2,332,000	2,554,000
Contractual stated interest rate (percent)			5.88%
Effective interest rate (percent)			5.99%
Samsonite \| Mortgages
Debt Instrument [Line Items]
Total principal			$ 21,626,000	22,085,000
Contractual stated interest rate (percent)			6.08%
Effective interest rate (percent)			5.17%
Highway 94 loan \| Mortgages
Debt Instrument [Line Items]
Total principal			$ 16,058,000	16,497,000
Contractual stated interest rate (percent)			3.75%
Effective interest rate (percent)			4.70%
AIG Loan II \| Mortgages
Debt Instrument [Line Items]
Total principal			$ 126,970,000	0
Debt, net			$ 127,000,000
Contractual stated interest rate (percent)			4.15%
Effective interest rate (percent)			4.95%
Initial debt instrument term			10 years
BOA Loan \| Mortgages
Debt Instrument [Line Items]
Total principal			$ 375,000,000	375,000,000
Contractual stated interest rate (percent)			3.77%
Effective interest rate (percent)			3.92%
BOA/KeyBank Loan \| Mortgages
Debt Instrument [Line Items]
Total principal			$ 250,000,000	0
Debt, net			$ 250,000,000
Contractual stated interest rate (percent)			4.32%
Effective interest rate (percent)			4.16%
Initial debt instrument term			10 years
AIG Loan \| Mortgages
Debt Instrument [Line Items]
Total principal			$ 106,673,000	107,562,000
Contractual stated interest rate (percent)			4.96%
Effective interest rate (percent)			5.08%
Revolving Credit Facility \| Revolving Credit Facility
Debt Instrument [Line Items]
Total principal			$ 175,939,000	0
Effective interest rate (percent)			3.85%
Initial debt instrument term		3 years
Debt instrument extended term		1 year
Revolving Credit Facility \| Revolving Credit Facility \| LIBOR
Debt Instrument [Line Items]
Spread over variable rate (percent)			1.30%
2023 Term Loan
Debt Instrument [Line Items]
Effective interest rate (percent)			3.77%
2023 Term Loan \| LIBOR
Debt Instrument [Line Items]
Spread over variable rate (percent)			1.25%
2023 Term Loan \| Term Loans
Debt Instrument [Line Items]
Total principal			$ 200,000,000	0
Initial debt instrument term	4 years
2024 Term Loan
Debt Instrument [Line Items]
Effective interest rate (percent)			3.76%
2024 Term Loan \| LIBOR
Debt Instrument [Line Items]
Spread over variable rate (percent)			1.25%
2024 Term Loan \| Term Loans
Debt Instrument [Line Items]
Total principal			$ 400,000,000	0
Initial debt instrument term	5 years
2026 Term Loan
Debt Instrument [Line Items]
Effective interest rate (percent)			4.14%
2026 Term Loan \| LIBOR
Debt Instrument [Line Items]
Spread over variable rate (percent)			1.65%
2026 Term Loan \| Term Loans
Debt Instrument [Line Items]
Total principal			$ 150,000,000	0
Initial debt instrument term	7 years
Term Loan \| Term Loans
Debt Instrument [Line Items]
Total principal			$ 0	$ 715,000,000