Name:	frevsob_LiquidatedDamages
Namespace Prefix:	frevsob_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- References

No definition available.

Name:	frevsob_TerminationofPurchaseandSaleAgreementDetailsLineItems
Namespace Prefix:	frevsob_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Percentage of voting equity interests acquired at the acquisition date in the business combination.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI https://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

Name:	us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1D
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=123466505&loc=SL123495340-112611

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 3
-URI https://asc.fasb.org/extlink&oid=124435984&loc=d3e28555-108399

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

The designation of funds furnished by a borrower to a lender to assure future payments of the borrower's real estate taxes and insurance obligations with respect to a mortgaged property. Escrow deposits may be made for a variety of other purposes such as earnest money and contingent payments. This element excludes replacement reserves which are an escrow separately provided for within the US GAAP taxonomy.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.10)
-URI https://asc.fasb.org/extlink&oid=126897435&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 954
-SubTopic 440
-Section 50
-Paragraph 1
-Subparagraph (d)
-URI https://asc.fasb.org/extlink&oid=6491277&loc=d3e6429-115629

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

Escrow deposits related to property sales in noncash investing and financing activities.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 3
-URI https://asc.fasb.org/extlink&oid=126999549&loc=d3e4304-108586

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 5
-URI https://asc.fasb.org/extlink&oid=126999549&loc=d3e4332-108586

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-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 4
-URI https://asc.fasb.org/extlink&oid=126999549&loc=d3e4313-108586

Name:	us-gaap_EscrowDepositsRelatedToPropertySales
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Amount of litigation expense, including but not limited to legal, forensic, accounting, and investigative fees.

No definition available.

Name:	us-gaap_LitigationSettlementExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

The amount of expense in the period for the cost of other broker-dealers' executions of orders.

No definition available.

Name:	us-gaap_OrderFlowFees
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

This element represents those amounts set aside for the repair and replacement of real or personal property in the foreseen future. Such amount may be funded from sales revenue (for example; timeshare sales) or operating revenues; in a lump sum or installments (such as monthly); as per internal policy (for example: hotel operators), as required by contractual agreement (for example: sales contract); or by the terms of debt agreements.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.2,10)
-URI https://asc.fasb.org/extlink&oid=126734703&loc=d3e572229-122910

Name:	us-gaap_ReplacementReserveEscrow
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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The amount at risk under resale agreements (reverse repurchase agreements) is defined as the excess of the carrying amount of the resale agreements over the market value of assets delivered pursuant to the agreements by the counterparty to the registrant (or to a third party agent that has affirmatively agreed to act on behalf of the registrant) and not returned to the counterparty, except in exchange for their approximate market value in a separate transaction.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(m)(2)(ii))
-URI https://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

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

Name:	srt_OwnershipAxis=frevsob_PurchaseAndSaleAgreementMember
Namespace Prefix:
Data Type:	na
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Period Type:

Name:	us-gaap_RelatedPartyTransactionAxis=frevsob_KushnerRealtyAcquisitionLLCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_BusinessAcquisitionAxis=frevsob_PurchaseAndSaleAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: