Debt Instrument, Maximum Distribution, Percentage of FFO

No definition available.

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- 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

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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

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- Definition

Line Of Credit Facility, Increase (Decrease) In Maximum Borrowing Capacity

+ References

No definition available.

+ Details

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

- Definition

Line Of Credit Facility, Number Of Extensions

+ References

No definition available.

+ Details

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- Definition

Line of Credit Facility, Accordion Feature, Increase Limit

+ References

No definition available.

+ Details

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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

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Period Type:	duration

- Definition

Line of Credit Facility, Unused Capacity, Facility Fee Multiplier

+ References

No definition available.

+ Details

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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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- 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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- 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

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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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- Definition

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

+ References

No definition available.

+ Details

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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

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- Details

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Credit Facilities - Credit Facility (Details)				1 Months Ended
Credit Facilities - Credit Facility (Details)	Jul. 02, 2018 EUR (€)	Jul. 02, 2018 USD ($)	Jul. 24, 2017 USD ($) extension	Apr. 30, 2019	Mar. 31, 2019 EUR (€)	Mar. 31, 2019 USD ($)	Jun. 30, 2018 USD ($)
Credit Facility \| KeyBank National Association \| Unsecured debt
Line of Credit Facility [Line Items]
Maximum borrowing capacity (up to)		$ 914,400,000	$ 725,000,000				$ 722,200,000
Increase in aggregate commitments (up to)		35,600,000
Total line of credit commitment		950,000,000
Number of extensions \| extension			1
Extension term			1 year
Weighted-average effective interest rate					2.60%	2.60%
Available for future borrowings						$ 149,200,000
Credit Facility \| KeyBank National Association \| Unsecured debt \| Federal Funds
Line of Credit Facility [Line Items]
Interest rate spread			0.50%
Credit Facility \| KeyBank National Association \| Unsecured debt \| LIBOR
Line of Credit Facility [Line Items]
Interest rate spread			1.00%
Credit Facility \| KeyBank National Association \| Unsecured debt \| LIBOR \| Minimum
Line of Credit Facility [Line Items]
Interest rate spread			1.60%
Credit Facility \| KeyBank National Association \| Unsecured debt \| LIBOR \| Maximum
Line of Credit Facility [Line Items]
Interest rate spread			2.20%
Credit Facility \| KeyBank National Association \| Unsecured debt \| Base Rate \| Minimum
Line of Credit Facility [Line Items]
Interest rate spread			0.60%
Credit Facility \| KeyBank National Association \| Unsecured debt \| Base Rate \| Maximum
Line of Credit Facility [Line Items]
Interest rate spread			1.20%
Credit Facility \| KeyBank National Association \| Unsecured debt \| Revolving Credit Facility
Line of Credit Facility [Line Items]
Maximum borrowing capacity (up to)						632,000,000
Increase in maximum borrowing capacity		132,000,000
Facility fee multiplier			0.003
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 Facility
Line of Credit Facility [Line Items]
Maximum borrowing capacity (up to)					€ 246,481,489.42	$ 276,517,000
Increase in maximum borrowing capacity	€ 51,800,000	$ 60,200,000
Subsequent Event
Line of Credit Facility [Line Items]
Maximum distribution as percentage of FFO				95.00%
Maximum distribution as percentage of FFO, under exception				100.00%