Organization and Formation of Company - Additional Information (Detail)	3 Months Ended
Mar. 31, 2015 Property sqft State Joint_Ventures
Organization and Formation of Company [Line Items]
Ownership interest of sole general partner	96.20%
Company's ownership interest in the general partners	100.00%fr_OwnershipInterestInGeneralPartner
Ownership interest of limited partner	3.80%
Number of joint ventures	2fr_NumberOfJointVentures
Number of industrial properties sold	9fr_NumberOfIndustrialPropertiesSold
Gross leasable area (GLA) of industrial properties sold	500,000
Number of industrial properties owned	629us-gaap_NumberOfRealEstateProperties
Number of states in which industrial properties are located	25
Gross leasable area (GLA) of industrial properties owned	63,000,000us-gaap_AreaOfRealEstateProperty
2003 Net Lease Joint Venture
Organization and Formation of Company [Line Items]
Noncontrolling equity ownership interest	15.00%
Number of industrial properties sold	1
Gross leasable area (GLA) of industrial properties sold	800,000
2007 Europe Joint Venture
Organization and Formation of Company [Line Items]
Noncontrolling equity ownership interest	10.00%
Number of industrial properties owned	0

Number of industrial properties sold.

No definition available.

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Namespace Prefix:	fr_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of joint ventures that the entity owns a non-controlling interest in as of the balance sheet date.

+ References

No definition available.

+ Details

Name:	fr_NumberOfJointVentures
Namespace Prefix:	fr_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Details

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Data Type:	xbrli:stringItemType
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- Definition

Ownership interest in general partner.

+ References

No definition available.

+ Details

Name:	fr_OwnershipInterestInGeneralPartner
Namespace Prefix:	fr_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Square footage of industrial properties sold.

+ References

No definition available.

+ Details

Name:	fr_SquareFootageOfIndustrialPropertiesSold
Namespace Prefix:	fr_
Data Type:	num:areaItemType
Balance Type:	na
Period Type:	duration

- Definition

Area of a real estate property.

+ References

No definition available.

+ Details

Name:	us-gaap_AreaOfRealEstateProperty
Namespace Prefix:	us-gaap_
Data Type:	num:areaItemType
Balance Type:	na
Period Type:	instant

- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 323

-SubTopic 10

-Section 50

-Paragraph 3

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=6382943&loc=d3e33918-111571

+ Details

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

- Definition

The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity.

+ References

No definition available.

+ Details

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

- Definition

The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

+ References

No definition available.

+ Details

Name:	us-gaap_MinorityInterestOwnershipPercentageByParent
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
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

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

- Definition

The number of states the entity operates in as of the balance sheet date.

+ References

No definition available.

+ Details

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

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=fr_TwoThousandSevenEuropeJointVentureMember
Namespace Prefix:
Data Type:	na
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- Details

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