Represents the contract purchase of the real estate investment property.

No definition available.

Name:	brt_RealEstateInvestmentPropertyContractPurchasePrice
Namespace Prefix:	brt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This element represents acquisition-related costs incurred in connection with real estate investments acquired other than through foreclosure which costs have been expensed during the period.

+ References

No definition available.

+ Details

Name:	brt_RealEstateOtherAcquisitionsCostsExpensed
Namespace Prefix:	brt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399

+ Details

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

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ 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 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentTerm
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of units in a real estate property owned as of the balance sheet date.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfUnitsInRealEstateProperty
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The cash outflow associated with the investment in or advances to an entity in which the reporting entity shares control of the entity with another party or group.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3213-108585

+ Details

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

- Definition

Amount of acquisition of long-lived, physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

+ References

No definition available.

+ Details

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

- 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_RealEstatePropertiesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of the Variable Interest Entity's (VIE) voting interest owned by (or beneficial interest in) the reporting entity (directly or indirectly).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 5A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=77990344&loc=SL6759159-111685

+ Details

Name:	us-gaap_VariableInterestEntityOwnershipPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=us-gaap_CorporateJointVentureMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis=us-gaap_VariableInterestEntityPrimaryBeneficiaryMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis=us-gaap_ApartmentBuildingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=brt_PropertyAcquisitionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=us-gaap_MortgagesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementGeographicalAxis=brt_MadisonALMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementGeographicalAxis=brt_BoerneTXMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis=us-gaap_LandMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementGeographicalAxis=brt_FredricksburgVAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_MortgagesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
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Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementGeographicalAxis=brt_OcoeeFLMember
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Acquisitions and Dispositions - Property Acquisitions (Details)					3 Months Ended
	Feb. 06, 2018 USD ($) property_unit	Dec. 14, 2017 USD ($) property_unit	Dec. 07, 2017 USD ($) property_unit	Nov. 04, 2016 USD ($) property_unit	Dec. 31, 2017 USD ($) property_unit
Real Estate Properties
No. of Units \| property_unit					9,684
Corporate Joint Venture \| VIE \| Multi-family \| Property Acquisition
Real Estate Properties
No. of Units \| property_unit					324
Purchase Price					$ 30,420,000
Initial BRT Equity					8,236,000
Capitalized acquisition costs					491,000
Corporate Joint Venture \| VIE \| Multi-family \| Property Acquisition \| Mortgages payable
Real Estate Properties
Acquisition Mortgage Debt					24,200,000
Corporate Joint Venture \| VIE \| Madison, AL \| Multi-family \| Property Acquisition
Real Estate Properties
No. of Units \| property_unit			204
Purchase Price			$ 18,420,000
Initial BRT Equity			$ 4,456,000
Ownership Percentage			80.00%
Capitalized acquisition costs			$ 247,000
Corporate Joint Venture \| VIE \| Madison, AL \| Multi-family \| Property Acquisition \| Mortgages payable
Real Estate Properties
Acquisition Mortgage Debt			$ 15,000,000
Corporate Joint Venture \| VIE \| Boerne, TX \| Multi-family \| Property Acquisition
Real Estate Properties
No. of Units \| property_unit		120
Purchase Price		$ 12,000,000
Initial BRT Equity		$ 3,780,000
Ownership Percentage		80.00%
Capitalized acquisition costs		$ 244,000
Corporate Joint Venture \| VIE \| Boerne, TX \| Multi-family \| Property Acquisition \| Mortgages payable
Real Estate Properties
Acquisition Mortgage Debt		9,200,000
Corporate Joint Venture \| VIE \| Boerne, TX \| Land \| Property Acquisition
Real Estate Properties
Land acquisition		$ 500,000
Corporate Joint Venture \| VIE \| Fredricksburg, VA \| Multi-family \| Property Acquisition
Real Estate Properties
No. of Units \| property_unit				220
Purchase Price				$ 38,490,000
Initial BRT Equity				$ 8,720,000
Ownership Percentage				80.00%
Capitalized acquisition costs				$ 643,000
Corporate Joint Venture \| VIE \| Fredricksburg, VA \| Multi-family \| Property Acquisition \| Mortgages payable
Real Estate Properties
Acquisition Mortgage Debt				$ 29,940,000
Mortgages payable
Real Estate Properties
Acquisition Mortgage Debt					$ 24,200,000
Subsequent event \| Corporate Joint Venture \| VIE \| Ocoee, FL \| Multi-family \| Property Acquisition
Real Estate Properties
No. of Units \| property_unit	522
Purchase Price	$ 71,347,000
Acquisition Mortgage Debt	$ 12,370,000
Ownership Percentage	50.00%
Subsequent event \| Corporate Joint Venture \| VIE \| Ocoee, FL \| Multi-family \| Property Acquisition \| Mortgages payable
Real Estate Properties
Acquisition Mortgage Debt	$ 53,100,000
Subsequent event \| Mortgages payable \| Corporate Joint Venture \| VIE \| Ocoee, FL \| Multi-family \| Property Acquisition \| Mortgages payable
Real Estate Properties
Interest rate	3.90%
Interest only period	7 years