XML 52 R38.htm IDEA: XBRL DOCUMENT
v3.21.2

Stockholders’ Equity of the Company and Partners' Capital of the Operating Partnership - Additional Information (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Sep. 30, 2021 | Sep. 30, 2021 | Sep. 30, 2020 | Feb. 14, 2020
Class of Stock [Line Items] |  |  |  |
Proceeds from the Issuance of Common Stock, Net of Underwriter's Discount |  | $ 59,008 | $ 78,718 |
ATM [Member] |  |  |  |
Class of Stock [Line Items] |  |  |  |
Stock Issued During Period, Shares, New Issues | 1,076,955 |  |  |
Proceeds from the Issuance of Common Stock, Net of Underwriter's Discount | $ 59,008 |  |  |
Commission To Sales Agent | $ 596 |  |  |
ATM [Member] |  |  |  |
Class of Stock [Line Items] |  |  |  |
Shares of company stock issuable under an at-the-market offering |  |  |  | 14,000,000
Aggregate Gross Sale Proceeds |  |  |  | $ 500,000

X
- Definition The aggregate offering price of the distribution agreement for the at-the-market offering. + References No definition available. + Details
Name: | fr_AggregateGrossSaleProceeds
Namespace Prefix: | fr_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Commission To Sales Agent + References No definition available. + Details
Name: | fr_CommissionToSalesAgent
Namespace Prefix: | fr_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Saleable Company Common Stock + References No definition available. + Details
Name: | fr_SaleableCompanyCommonStock
Namespace Prefix: | fr_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_ClassOfStockLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The cash inflow from the additional capital contribution to the entity. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 14 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3255-108585 + Details
Name: | us-gaap_ProceedsFromIssuanceOfCommonStock
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Number of new stock issued during the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=123467817&loc=d3e21463-112644 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187085-122770 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(28)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_StockIssuedDuringPeriodSharesNewIssues
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_StatementClassOfStockAxis=fr_ATMMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SubsidiarySaleOfStockAxis=fr_ATMMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |