Equity interest acquired.

No definition available.

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

- Definition

Fair Value Input Capitalization Rates

+ References

No definition available.

+ Details

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

- Definition

In a Business combination, this element represents the amount of gain/loss recognized by the entity as a result of the change in control of the underlying real estate asset. This transaction was accounted for as a step acquisition utilizing the purchase method of accounting.

+ References

No definition available.

+ Details

Name:	fr_GainLossOnChangeInControlOfInterests
Namespace Prefix:	fr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Gross proceeds from the sale of industrial properties .

+ References

No definition available.

+ Details

Name:	fr_GrossProceedsFromSaleOfIndustrialProperties
Namespace Prefix:	fr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Impairment of Real Estate Other.

+ References

No definition available.

+ Details

Name:	fr_ImpairmentOfRealEstateOther
Namespace Prefix:	fr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Number of industrial properties acquired.

+ References

No definition available.

+ Details

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

- Definition

Number of Industrial Properties Held for Sale.

+ References

No definition available.

+ Details

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

- Definition

Number of industrial properties sold.

+ References

No definition available.

+ Details

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

- Definition

Number of Industrial Properties Transferred to Lender.

+ References

No definition available.

+ Details

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

- Definition

Number Of Industrial Properties With Mortgage Loan Receivable With Bankrupt Tenant

+ References

No definition available.

+ Details

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

- Definition

Number of land parcels sold.

+ References

No definition available.

+ Details

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

- Definition

Percentage of consideration paid of net fair value of acquisition.

+ References

No definition available.

+ Details

Name:	fr_PercentageOfConsiderationPaidOfNetFairValueOfAcquisition
Namespace Prefix:	fr_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Purchase Price of Industrial Properties.

+ References

No definition available.

+ Details

Name:	fr_PurchasePriceOfIndustrialProperties
Namespace Prefix:	fr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	fr_RealEstateInvestmentsLineItems
Namespace Prefix:	fr_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Gross leasable area (GLA) of impaired industrial property

+ References

No definition available.

+ Details

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

- Definition

Square Footage of Industrial Properties Held for Sale.

+ References

No definition available.

+ Details

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

- 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

Square Footage Of Industrial Property Transferred To Lender.

+ References

No definition available.

+ Details

Name:	fr_SquareFootageOfIndustrialPropertyTransferredToLender
Namespace Prefix:	fr_
Data Type:	num:areaItemType
Balance Type:	na
Period Type:	instant

- Definition

Square Footage of Real Estate Properties Acquired.

+ References

No definition available.

+ Details

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

- Definition

Amount of cash paid to acquire the entity.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141R

-Paragraph 68

-Subparagraph f(1)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141

-Paragraph 51

-Subparagraph d

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

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

- Definition

Fair Value of the liabilities incurred by the acquirer to former owners of the acquiree, including the fair value of any contingent consideration. If liabilities transferred as consideration remain within the combined entity after the business combination (for example, because the assets or liabilities were transferred to the acquiree rather than to its former owners), and the acquirer therefore retains control of them; in that situation, the acquirer measures those liabilities at their carrying amounts immediately before the acquisition date.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 30

-Section 25

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6911189&loc=d3e6405-128476

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141R

-Paragraph 68

-Subparagraph f(3)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141

-Paragraph 51

-Subparagraph d

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141R

-Paragraph 39, 40, 41

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 30

-Section 30

-Paragraph 8

-URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6613-128477

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 30

-Section 30

-Paragraph 7

-URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6578-128477

+ Details

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

- Definition

Amount of acquisition cost of a business combination allocated to land included in real estate.

+ References

No definition available.

+ Details

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

- Definition

The difference between the carrying value and the sale price of real estate or properties that were intended to be sold or held for capital appreciation or rental income. This element refers to the gain (loss) included in earnings and not to the cash proceeds of the sale. This element is a noncash adjustment to net income when calculating net cash generated by operating activities using the indirect method.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3602-108585

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 28

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

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

- Definition

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. An amount representing an agreement for an unconditional promise by the maker to pay the Company (holder) a definite sum of money at a future date(s).

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.3(b))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 3

-Subparagraph b

-Article 5

+ Details

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

- Definition

Amount representing an agreement for an unconditional promise by the maker to pay the entity (holder) a definite sum of money at a future date. Such amount may include accrued interest receivable in accordance with the terms of the note. The note also may contain provisions and related items including a discount or premium, payable on demand, secured, or unsecured, interest bearing or noninterest bearing, among a myriad of other features and characteristics. Excludes amounts related to receivables held-for-sale.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.10(3))

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 10

-Subparagraph 3

-Article 9

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

- Definition

Net amount of the investment in a contractual right to receive money on demand or on fixed or determinable dates that is recognized as an asset in the creditor's statement of financial position. Examples include, but are not limited to, credit card receivables, notes receivable and receivables relating to lessor's rights to payments from leases other than operating leases that have been recorded as assets. Excludes trade accounts receivable with contractual maturity of one year or less and arose from the sale of goods or services.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.3)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 3

-Article 5

+ Details

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

- Definition

Disclosure of the unamortized amount of the discount on the note or receivable which is deducted from the face amount of the receivable or loan. The discount or premium is the difference between the present value and the face amount.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 45

-Paragraph 1A

-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28541-108399

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-Publisher AICPA

-Name Accounting Principles Board Opinion (APB)

-Number 21

-Paragraph 16

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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Balance Type:	credit
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Investment in Real Estate - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended					3 Months Ended	12 Months Ended			1 Months Ended		12 Months Ended			12 Months Ended
	Dec. 31, 2012 Parcels Property sqft	Dec. 31, 2011 sqft Parcels Property	Dec. 31, 2010 Property Parcels sqft	Sep. 20, 2011 sqft	Dec. 31, 2012 Mortgage Loans on Real Estate [Member]	Mar. 31, 2010 Grand Rapids Property [Member] sqft	Dec. 31, 2012 Discontinuing operations [Member]	Dec. 31, 2011 Discontinuing operations [Member]	Dec. 31, 2010 Discontinuing operations [Member]	May 26, 2012 2003 Net Lease Joint Venture [Member] Property	Feb. 13, 2012 2003 Net Lease Joint Venture [Member] Property	Dec. 31, 2012 2003 Net Lease Joint Venture [Member] Property	Dec. 31, 2011 2003 Net Lease Joint Venture [Member] Property	May 26, 2011 2003 Net Lease Joint Venture [Member]	Dec. 31, 2010 Former Joint Venture Partner [Member] Property
Real Estate Investments [Line Items]
Number of industrial properties acquired	1	1	3							1	1	1	1		1
Gross leasable area (GLA) of industrial properties acquired	400,000	700,000	500,000
Purchase price of industrial properties	$ 21,819	$ 30,625	$ 22,408
Equity Interest Acquired											85.00%	85.00%	85.00%	85.00%
Carrying value of mortgage loan assumed from acquisition	12,026	24,417
Cash payment of acquisition	8,324	5,277
Percentage of consideration paid of net fair value of acquisition	85.00%	85.00%
Approximate gain due to the difference between carrying value and fair value of acquisition	776	689
Purchase price of land parcels	46,695
Capitalization rate used for calculating estimated fair value of industrial properties acquired	7.30%	8.40%
Number of industrial properties sold	28	36	13
Gross leasable area (GLA) of industrial properties sold	4,200,000	2,900,000	1,100,000
Gross proceeds from the sale of industrial properties and land parcel	85,561	86,643	71,019
Gain on sale of real estate	16,442	21,789	11,951				12,665	20,419	11,092
Number of land parcels sold	1	1	1
Gross leasable area (GLA) of industrial property transferred to lender		400,000		400,000
Number of industrial properties transferred to lender		1
Number of industrial properties held for sale	3
Gross leasable area (GLA) of industrial properties held for sale	400,000
Notes receivable outstanding	41,201	55,502			7,660
Net discount of notes receivable outstanding	255	319			255
Fair value of notes receivable	44,783	58,734
Carrying value of mortgage loan receivable	7,405
Number of industrial properties with mortgage loan receivable with bankrupt tenant	1
Impairment of Real Estate	$ 1,246	$ (2,661)	$ 185,397			$ 9,155
Gross leasable area (GLA) of impaired industrial property						300,000