Number of Land Parcels

No definition available.

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- Definition

The amount of assets acquired.

+ References

No definition available.

+ Details

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Namespace Prefix:	fr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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
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-Topic 470
-SubTopic 20
-Section 50
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Namespace Prefix:	us-gaap_
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

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
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-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Balance Type:	na
Period Type:	instant

- Definition

The number of real estate properties owned as of the balance sheet date.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The cash inflow from sale of buildings.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
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+ Details

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

- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

No definition available.

+ Details

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- Details

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- Details

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Subsequent Events - Additional Information (Details) $ in Thousands	1 Months Ended	6 Months Ended
	Jul. 26, 2019 USD ($) Property	Jun. 30, 2019 USD ($) Property	Jul. 23, 2019 USD ($)
Subsequent Event [Line Items]
Number of industrial properties		462
Long-term Debt, Gross \| $		$ 1,388,845
Acquisition Activity
Subsequent Event [Line Items]
Number of industrial properties		4
Number of Land Parcels		4
Purchase price of industrial properties acquired \| $		$ 48,582
Disposition Activity
Subsequent Event [Line Items]
Number of industrial properties		2
Proceeds from sale of industrial properties \| $		$ 12,091
Subsequent Event \| Acquisition Activity
Subsequent Event [Line Items]
Number of industrial properties	3
Number of Land Parcels	2
Purchase price of industrial properties acquired \| $	$ 31,676
Subsequent Event \| Disposition Activity
Subsequent Event [Line Items]
Number of industrial properties	1
Number of Land Parcels	1
Proceeds from sale of industrial properties \| $	$ 6,244
2029 II Private Placement Notes
Subsequent Event [Line Items]
Long-term Debt, Gross \| $			$ 150,000
2029 II Private Placement Notes \| Subsequent Event
Subsequent Event [Line Items]
Long-term Debt, Gross \| $			$ 150,000
Effective Interest Rate			3.97%