Acquisitions and Dispositions - Property Acquisitions (Details)	3 Months Ended
Mar. 31, 2019 USD ($) property property_Unit	Mar. 31, 2018 USD ($) property
Real Estate Properties [Line Items]
No. of Units \| property_Unit	10,008
Initial BRT Equity	$ 11,231,000	$ 12,370,000
Corporate Joint Venture \| VIE \| Apartment Building \| Property Acquisition
Real Estate Properties [Line Items]
No. of Units \| property		1,108
Purchase Price		$ 148,576,000
Initial BRT Equity		27,549,000
Capitalized Acquisition Costs		$ 1,814,000
Corporate Joint Venture \| VIE \| Kannapolis, North Carolina \| Apartment Building \| Property Acquisition
Real Estate Properties [Line Items]
No. of Units \| property	312
Purchase Price	$ 48,065,000
Initial BRT Equity	$ 11,231,000
Ownership Percentage	65.00%
Capitalized Acquisition Costs	$ 559,000
Corporate Joint Venture \| VIE \| Ocoee, FL \| Apartment Building \| Property Acquisition
Real Estate Properties [Line Items]
No. of Units \| property		522
Purchase Price		$ 71,347,000
Initial BRT Equity		$ 12,370,000
Ownership Percentage		50.00%
Capitalized Acquisition Costs		$ 1,047,000
Corporate Joint Venture \| VIE \| Lawrenceville, GA \| Apartment Building \| Property Acquisition
Real Estate Properties [Line Items]
No. of Units \| property		586
Purchase Price		$ 77,229,000
Initial BRT Equity		$ 15,179,000
Ownership Percentage		50.00%
Capitalized Acquisition Costs		$ 767,000
Acquisition Mortgages Debt \| Corporate Joint Venture \| VIE \| Apartment Building \| Property Acquisition
Real Estate Properties [Line Items]
Acquisition Mortgage Debt		107,507,000
Acquisition Mortgages Debt \| Corporate Joint Venture \| VIE \| Kannapolis, North Carolina \| Apartment Building \| Property Acquisition
Real Estate Properties [Line Items]
Acquisition Mortgage Debt	$ 33,347,000
Acquisition Mortgages Debt \| Corporate Joint Venture \| VIE \| Ocoee, FL \| Apartment Building \| Property Acquisition
Real Estate Properties [Line Items]
Acquisition Mortgage Debt		53,060,000
Acquisition Mortgages Debt \| Corporate Joint Venture \| VIE \| Lawrenceville, GA \| Apartment Building \| Property Acquisition
Real Estate Properties [Line Items]
Acquisition Mortgage Debt		$ 54,447,000

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

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

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_StatementGeographicalAxis=brt_KannapolisNCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_StatementGeographicalAxis=brt_LawrencevilleGAMember
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: