XML 103 R75.htm IDEA: XBRL DOCUMENT
v3.19.3.a.u2

Derivatives - Fair Value Measurements on Recurring Basis (Details) $ in Thousands | Dec. 31, 2019 USD ($)
--- | ---
2014 Swaps |
Fair Value On Recurring Basis [Line Items] |
Hedging Instrument, Liability, Fair Value | $ (1,478)
2014 Swaps | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) |
Fair Value On Recurring Basis [Line Items] |
Hedging Instrument, Liability, Fair Value | 0
2014 Swaps | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) |
Fair Value On Recurring Basis [Line Items] |
Hedging Instrument, Liability, Fair Value | (1,478)
2014 Swaps | Fair Value, Measurements, Recurring | Unobservable Inputs (Level 3) |
Fair Value On Recurring Basis [Line Items] |
Hedging Instrument, Liability, Fair Value | 0
2015 Swaps |
Fair Value On Recurring Basis [Line Items] |
Hedging Instrument, Liability, Fair Value | (1,711)
2015 Swaps | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) |
Fair Value On Recurring Basis [Line Items] |
Hedging Instrument, Liability, Fair Value | 0
2015 Swaps | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) |
Fair Value On Recurring Basis [Line Items] |
Hedging Instrument, Liability, Fair Value | (1,711)
2015 Swaps | Fair Value, Measurements, Recurring | Unobservable Inputs (Level 3) |
Fair Value On Recurring Basis [Line Items] |
Hedging Instrument, Liability, Fair Value | $ 0

X
- Definition Fair Value On Recurring Basis [Line Items] + References No definition available. + Details
Name: | fr_FairValueOnRecurringBasisLineItems
Namespace Prefix: | fr_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Fair value of all liability derivatives designated as cash flow hedging instruments. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4B -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5624163-113959 + Details
Name: | us-gaap_CashFlowHedgeDerivativeInstrumentLiabilitiesAtFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=fr_InterestRateSwapOneMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=fr_InterestRateSwapTwoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |