Debt Instrument, Basis Spread On Base Rate

No definition available.

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- Definition

Debt Instrument, Maximum Distribution, Percentage of FFO

+ References

No definition available.

+ Details

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- Definition

Debt Instrument, Maximum Distribution Under Exemption, Percentage Of AFFO

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Maximum Distribution Under Exemption, Percentage Of FFO

+ References

No definition available.

+ Details

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- Definition

Line Of Credit Facility, Accordion Feature, Higher Borrowing Capacity Option

+ References

No definition available.

+ Details

Name:	gnl_LineOfCreditFacilityAccordionFeatureHigherBorrowingCapacityOption
Namespace Prefix:	gnl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line of Credit Facility, Commitment Fee Percentage, Threshold, Unused Capacity as a Percentage of Current Capacity

+ References

No definition available.

+ Details

Name:	gnl_LineOfCreditFacilityCommitmentFeePercentageThresholdUnusedCapacityAsPercentageOfCurrentCapacity
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Data Type:	num:percentItemType
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Period Type:	instant

- Definition

Line Of Credit Facility, Number Of Extensions

+ References

No definition available.

+ Details

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Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Line of Credit Facility, Accordion Feature, Increase Limit

+ References

No definition available.

+ Details

Name:	gnl_LineofCreditFacilityAccordionFeatureIncreaseLimit
Namespace Prefix:	gnl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line of Credit Facility, Extension Term

+ References

No definition available.

+ Details

Name:	gnl_LineofCreditFacilityExtensionTerm
Namespace Prefix:	gnl_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Line of Credit Facility, Unused Capacity, Facility Fee Multiplier

+ References

No definition available.

+ Details

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Namespace Prefix:	gnl_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- 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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Balance Type:	na
Period Type:	duration

- 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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Period Type:	duration

- 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=120391452&loc=d3e13212-122682

+ Details

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

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

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

- Definition

The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

Weighted average interest rate of long-term debt outstanding calculated at point in time.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	instant

- Details

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- Details

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- Details

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- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
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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

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- Details

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- Details

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- Details

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Credit Facilities - Narrative (Details)			3 Months Ended	9 Months Ended
Credit Facilities - Narrative (Details)	Aug. 01, 2019 USD ($) extension	Jul. 24, 2017	Jun. 30, 2020	Sep. 30, 2020 USD ($)	Sep. 30, 2020 EUR (€)	Jul. 31, 2019 USD ($)
Line of Credit Facility [Line Items]
Maximum distribution as percentage of FFO			100.00%	100.00%
Maximum distribution as percentage of AFFO				105.00%
Maximum distribution as percentage of FFO, under exception			105.00%
Credit Facility
Line of Credit Facility [Line Items]
Weighted-average effective interest rate				2.50%	2.50%
Credit Facility \| Federal Funds
Line of Credit Facility [Line Items]
Basis spread on base rate determination		0.50%
Credit Facility \| LIBOR
Line of Credit Facility [Line Items]
Basis spread on base rate determination		1.00%
Credit Facility \| Revolving Credit Facility
Line of Credit Facility [Line Items]
Available for future borrowings				$ 92,000,000.0
Credit Facility \| KeyBank National Association \| Unsecured debt
Line of Credit Facility [Line Items]
Increase in aggregate commitments	$ 515,000,000.0
Total line of credit commitment	$ 1,750,000,000					$ 950,000,000.0
Credit Facility \| KeyBank National Association \| Unsecured debt \| Revolving Credit Facility
Line of Credit Facility [Line Items]
Maximum borrowing capacity				835,000,000.0
Number of extensions \| extension	2
Extension term	6 months
Facility fee multiplier		0.0030
Credit Facility \| KeyBank National Association \| Unsecured debt \| Revolving Credit Facility \| Above Threshold
Line of Credit Facility [Line Items]
Unused capacity commitment fee		0.25%
Commitment fee percentage		50.00%
Credit Facility \| KeyBank National Association \| Unsecured debt \| Revolving Credit Facility \| Below Threshold
Line of Credit Facility [Line Items]
Unused capacity commitment fee		0.15%
Commitment fee percentage		50.00%
Credit Facility \| KeyBank National Association \| Unsecured debt \| Term Loan Facility
Line of Credit Facility [Line Items]
Maximum borrowing capacity				$ 421,600,000	€ 359,600,000
Credit Facility Amendment
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 1,235,000,000
Credit Facility Amendment \| Revolving Credit Facility \| LIBOR \| Minimum
Line of Credit Facility [Line Items]
Interest rate spread	1.45%
Credit Facility Amendment \| Revolving Credit Facility \| LIBOR \| Maximum
Line of Credit Facility [Line Items]
Interest rate spread	2.05%
Credit Facility Amendment \| Revolving Credit Facility \| Base Rate \| Minimum
Line of Credit Facility [Line Items]
Interest rate spread	0.45%
Credit Facility Amendment \| Revolving Credit Facility \| Base Rate \| Maximum
Line of Credit Facility [Line Items]
Interest rate spread	1.05%
Credit Facility Amendment \| Term Loan \| LIBOR \| Minimum
Line of Credit Facility [Line Items]
Interest rate spread	1.40%
Credit Facility Amendment \| Term Loan \| LIBOR \| Maximum
Line of Credit Facility [Line Items]
Interest rate spread	2.00%
Credit Facility Amendment \| Term Loan \| Base Rate \| Minimum
Line of Credit Facility [Line Items]
Interest rate spread	0.40%
Credit Facility Amendment \| Term Loan \| Base Rate \| Maximum
Line of Credit Facility [Line Items]
Interest rate spread	1.00%