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

GLA of Industrial Property Transferred To Lender

+ References

No definition available.

+ Details

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

- Definition

Gross Area of Land Parcels Non Strategic Assets Held For Sale

+ References

No definition available.

+ Details

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

- Definition

Gross Area of Land Parcels Non Strategic Assets Other

+ References

No definition available.

+ Details

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

- Definition

The charge against earnings in the period to reduce the carrying amount of real property to fair value. Includes amounts in income from continuing operations and income from discontinued operations.

+ References

No definition available.

+ Details

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

- Definition

Impairment Of Real Estates Non Strategic Assets Held For Sale

+ References

No definition available.

+ Details

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

- Definition

Impairment reversal of industrial properties and land parcels.

+ References

No definition available.

+ Details

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

- Details

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

- Details

Name:	fr_InvestmentsInRealEstateAdditionalTextualAbstract
Namespace Prefix:	fr_
Data Type:	xbrli:stringItemType
Balance Type:	na
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:	instant

- Definition

Number of industrial properties Non Strategic Assets Held For Sale

+ References

No definition available.

+ Details

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

- Definition

Number of industrial properties Non Strategic Assets Other

+ References

No definition available.

+ Details

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

- 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:	instant

- Definition

Number of operations of industrial properties held for sale.

+ References

No definition available.

+ Details

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

- Definition

This is the acquisition of equity for a property within the 2003 Net Lease Joint Venture.

+ References

No definition available.

+ Details

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

- 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

Sale of Industrial Properties of GLA Area in square Foot.

+ References

No definition available.

+ Details

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

- Definition

Square Footage Of Real Estate Property Acquired

+ References

No definition available.

+ Details

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

- Definition

Square Footage Of Real Estate Property Held For Sale

+ References

No definition available.

+ Details

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

- Definition

Square Footage Of Real Estate Property Non Strategic Assets Held For Sale

+ References

No definition available.

+ Details

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

- Definition

Square Footage Of Real Estate Property Non Strategic Assets Other

+ References

No definition available.

+ Details

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

- Definition

Square Footage Of Real Estate Property Sold

+ References

No definition available.

+ Details

Name:	fr_SquareFootageOfRealEstatePropertySold
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 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 2: 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.

+ 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

Reference 2: 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

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 Accounting Standards Codification

-Topic 805

-SubTopic 30

-Section 30

-Paragraph 7

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

Reference 5: 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 6: http://www.xbrl.org/2003/role/presentationRef

-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.

+ Details

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

- Definition

The amount of acquisition cost of a business combination allocated to land and building to be used in the normal course of business, not including assets that are held-for-sale.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141

-Paragraph 51

-Subparagraph e

-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 37

-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_BusinessAcquisitionPurchasePriceAllocationProperty
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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 Statement of Financial Accounting Standard (FAS)

-Number 159

-Paragraph 18

-Subparagraph f

-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 AICPA

-Name Accounting Principles Board Opinion (APB)

-Number 18

-Paragraph 20

-Subparagraph a (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 3: 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 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 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.

Reference 2: 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

+ Details

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

- Definition

Amount of the excess of the fair value of acquired net assets over the cost of an acquired business after pro rata reduction of the amounts that otherwise would have been assigned to acquired assets except financial assets other than investments accounted for by the equity method, assets to be disposed of by sale, deferred tax assets, prepaid assets relating to pension and postretirement benefit plans, and other current assets. This amount is considered an extraordinary item and often referred to as negative goodwill. This element is gross of the related tax effect.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141

-Paragraph 44, 45, 46

-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_GainOnPurchaseOfBusiness
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 SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 3

-Subparagraph b

-Article 5

Reference 2: 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

+ Details

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

- Definition

For an unclassified balance sheet, an 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, net of any write-downs taken for collection uncertainty on the part of the holder. 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. This amount does not include amounts related to receivables held-for-sale.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 3

-Article 5

Reference 2: 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

+ Details

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

Represents a total which may include the following: (1) land available-for-sale; (2) land available-for-development; (3) investments in building and building improvements; (4) tenant allowances; (5) developments in-process; (6) rental properties; and (7) other real estate investments.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.1(d))

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

+ Details

Name:	us-gaap_RealEstateInvestmentPropertyAtCost
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 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.

Reference 2: 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

+ Details

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

- Definition

The amount of square footage related to a real estate property.

+ References

No definition available.

+ Details

Name:	us-gaap_SquareFootageOfRealEstateProperty
Namespace Prefix:	us-gaap_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

Investment In Real Estate (Details Textual) (USD $) In Thousands, unless otherwise specified	2 Months Ended	12 Months Ended				3 Months Ended	12 Months Ended
	Feb. 28, 2012 sqft acre IndustrialProperty	Dec. 31, 2011 sqft acre IndustrialProperty	Dec. 31, 2010 sqft IndustrialProperty	Dec. 31, 2009 sqft IndustrialProperty	Oct. 22, 2010 IndustrialProperty acre	Mar. 31, 2010 Grand Rapids Property [Member] sqft	Dec. 31, 2009 Inland Empire [Member]	Dec. 31, 2011 Discontinued Operations [Member]	Dec. 31, 2010 Discontinued Operations [Member]	Dec. 31, 2009 Discontinued Operations [Member]	Dec. 31, 2011 2003 Net Lease Joint Venture [Member] sqft IndustrialProperty	May 26, 2011 2003 Net Lease Joint Venture [Member]
Additional Investment in Real Estate (Textual) [Abstract]
Ownership percentage purchased	85.00%	85.00%										85.00%
Interest on purchase of equity in property											15.00%
Investments In Real Estate (Additional Textual) [Abstract]
Discounted operations on the sale of real estate		$ 21,789	$ 11,951	$ 24,580				$ 20,419	$ 11,092	$ 24,206
Impairment of Real Estate		2,661	(194,552)	(6,934)		(9,155)	(6,934)
Gross Leasable Area (GLA) of industrial property owned	400,000	66,300,000				300,000	200,000				3,400,000
Investment in Real Estate (Textual) [Abstract]
Purchase price of industrial property		30,625	22,408	208
Number of industrial properties acquired		1	3	2
Square Footage Of Real Estate Property Acquired		700,000	500,000	1,100,000
Square Footage Of Real Estate Property Sold		2,900,000	1,100,000	1,900,000
Approximate cost of GLA				41,258
Carrying value of mortgage loan for funding of acquisition		24,417
Cash Acquired from Acquisition	8,324	5,277
Percentage of consideration paid of net fair value of acquisition		85.00%
Approximate gain due to the difference between carrying value and fair value of acquisition		689
Number of industrial properties Sold		36	13	15
Gross proceed from the sale of industrial properties		86,643	71,019	100,194
Gain on Sale of Real Estate		21,789	11,951	24,580				20,419	11,092	24,206
GLA of Industrial Property transferred to lender		400,000
Number of industrial properties		740									7
Square Footage Of Real Estate Property Held For Sale		4,800,000
Number of operations of industrial properties held for sale		46
Notes receivable outstanding		55,502	58,803
Net discount of notes receivable outstanding		319	383
Fair value of notes receivable		58,734	60,944
Number of industrial properties Non Strategic Assets Held For Sale		46			195
Gross Area of Land Parcels Non Strategic Assets Held for Sale		61			724
Number of industrial properties Non Strategic Assets Other		133
Gross Area of Land Parcels Non Strategic Assets Other		359
Square Footage of Real Estate Property Non Strategic Assets Held for Sale		4,800,000	16,400,000
Square Footage of Real Estate Property Non Strategic Assets Other		11,300,000
Impairment Of Real Estates Non Strategic Assets Held For Sale			185,397
Impairment reversal of industrial properties and land parcels		$ 9,678