Acquisitions and Dispositions - Schedule of Property Acquisitions (Details)									3 Months Ended		9 Months Ended
	May 31, 2016 USD ($) property_unit	May 11, 2016 USD ($) property_unit	May 06, 2016 USD ($) property_unit	Feb. 29, 2016 USD ($) property_unit	Feb. 01, 2016 USD ($) property_unit	Jan. 22, 2016 USD ($) property_unit	Nov. 18, 2015 USD ($) property_unit	Oct. 13, 2015 USD ($) a property_unit	Jun. 30, 2016 USD ($) property_unit	Jun. 30, 2015 USD ($)	Jun. 30, 2016 USD ($) property_unit	Jun. 30, 2015 USD ($)
Real Estate Properties
No. of Units | property_unit									8,973		8,973
Property Acquisition Costs									$ 1,408,000	$ 0	$ 2,418,000	$ 295,000
Business Acquisition, Transaction Costs								$ 63,000
Corporate Joint Venture | Variable Interest Entity, Primary Beneficiary | Multi-family | Property Acquisition
Real Estate Properties
No. of Units | property_unit									2,393		2,393
Contract Purchase Price									$ 205,350,000		$ 205,350,000
Initial BRT Equity											49,006,000
Property Acquisition Costs											2,418,000
Corporate Joint Venture | Variable Interest Entity, Primary Beneficiary | Multi-family | Property Acquisition | Mortgages
Real Estate Properties
Acquisition Mortgage Debt									$ 153,273,000		$ 153,273,000
Corporate Joint Venture | Variable Interest Entity, Primary Beneficiary | Charleston, SC | Multi-family
Real Estate Properties
Acres of land | a								41.5
Corporate Joint Venture | Variable Interest Entity, Primary Beneficiary | Charleston, SC | Multi-family | Property Acquisition
Real Estate Properties
No. of Units | property_unit								271
Contract Purchase Price								$ 3,625,000
Initial BRT Equity								$ 6,558,000
Interest in joint venture (as a percent)								65.00%
Property Acquisition Costs								$ 0
Corporate Joint Venture | Variable Interest Entity, Primary Beneficiary | Charleston, SC | Multi-family | Property Acquisition | Mortgages
Real Estate Properties
Acquisition Mortgage Debt								$ 0
Corporate Joint Venture | Variable Interest Entity, Primary Beneficiary | La Grange, GA | Multi-family | Property Acquisition
Real Estate Properties
No. of Units | property_unit							236
Contract Purchase Price							$ 22,800,000
Initial BRT Equity							$ 6,824,000
Interest in joint venture (as a percent)							100.00%
Property Acquisition Costs							$ 57,000
Corporate Joint Venture | Variable Interest Entity, Primary Beneficiary | La Grange, GA | Multi-family | Property Acquisition | Mortgages
Real Estate Properties
Acquisition Mortgage Debt							$ 16,051,000
Corporate Joint Venture | Variable Interest Entity, Primary Beneficiary | Katy, TX | Multi-family | Property Acquisition
Real Estate Properties
No. of Units | property_unit						268
Contract Purchase Price						$ 40,250,000
Initial BRT Equity						$ 8,150,000
Interest in joint venture (as a percent)						75.00%
Property Acquisition Costs						$ 382,000
Corporate Joint Venture | Variable Interest Entity, Primary Beneficiary | Katy, TX | Multi-family | Property Acquisition | Mortgages
Real Estate Properties
Acquisition Mortgage Debt						$ 30,750,000
Corporate Joint Venture | Variable Interest Entity, Primary Beneficiary | Macon, GA | Multi-family | Property Acquisition
Real Estate Properties
No. of Units | property_unit					240
Contract Purchase Price					$ 14,525,000
Initial BRT Equity					$ 3,250,000
Interest in joint venture (as a percent)					80.00%
Property Acquisition Costs					$ 158,000
Corporate Joint Venture | Variable Interest Entity, Primary Beneficiary | Macon, GA | Multi-family | Property Acquisition | Mortgages
Real Estate Properties
Acquisition Mortgage Debt					$ 11,200,000
Corporate Joint Venture | Variable Interest Entity, Primary Beneficiary | Southaven, MS | Multi-family | Property Acquisition
Real Estate Properties
No. of Units | property_unit				392
Contract Purchase Price				$ 35,000,000
Initial BRT Equity				$ 5,856,000
Interest in joint venture (as a percent)				60.00%
Property Acquisition Costs				$ 413,000
Corporate Joint Venture | Variable Interest Entity, Primary Beneficiary | Southaven, MS | Multi-family | Property Acquisition | Mortgages
Real Estate Properties
Acquisition Mortgage Debt				$ 28,000,000
Corporate Joint Venture | Variable Interest Entity, Primary Beneficiary | San Antonio, TX | Multi-family | Property Acquisition
Real Estate Properties
No. of Units | property_unit			288
Contract Purchase Price			$ 35,150,000
Initial BRT Equity			$ 6,688,000
Interest in joint venture (as a percent)			65.00%
Property Acquisition Costs			$ 539,000
Corporate Joint Venture | Variable Interest Entity, Primary Beneficiary | San Antonio, TX | Multi-family | Property Acquisition | Mortgages
Real Estate Properties
Acquisition Mortgage Debt			$ 26,400,000
Corporate Joint Venture | Variable Interest Entity, Primary Beneficiary | Dallas, TX | Multi-family | Property Acquisition
Real Estate Properties
No. of Units | property_unit		494
Contract Purchase Price		$ 37,000,000
Initial BRT Equity		$ 6,750,000
Interest in joint venture (as a percent)		50.00%
Property Acquisition Costs		$ 567,000
Corporate Joint Venture | Variable Interest Entity, Primary Beneficiary | Dallas, TX | Multi-family | Property Acquisition | Mortgages
Real Estate Properties
Acquisition Mortgage Debt		$ 27,938,000
Corporate Joint Venture | Variable Interest Entity, Primary Beneficiary | Columbia, SC | Multi-family | Property Acquisition
Real Estate Properties
No. of Units | property_unit	204
Contract Purchase Price	$ 17,000,000
Initial BRT Equity	$ 4,930,000
Interest in joint venture (as a percent)	80.00%
Property Acquisition Costs	$ 302,000
Corporate Joint Venture | Variable Interest Entity, Primary Beneficiary | Columbia, SC | Multi-family | Property Acquisition | Mortgages
Real Estate Properties
Acquisition Mortgage Debt	$ 12,934,000