Real Estate Properties (Details 2) (USD $)	3 Months Ended		3 Months Ended				0 Months Ended
	Dec. 31, 2012	Sep. 30, 2012 Commercial / mixed use Primary beneficiary RBH-TRB Newark Holdings LLC Mortgages Payable	Dec. 31, 2012 Multi Family	Dec. 31, 2012 Multi Family Primary beneficiary Purchase of properties item	Dec. 31, 2012 Multi Family Primary beneficiary Minimum Purchase of properties	Dec. 31, 2012 Multi Family Primary beneficiary Maximum Purchase of properties	Oct. 04, 2012 Multi Family Primary beneficiary North Charleston, SC Purchase of properties item	Nov. 15, 2012 Multi Family Primary beneficiary Cordova, TN Purchase of properties item	Nov. 19, 2012 Multi Family Primary beneficiary Decatur, GA Purchase of properties item
Real Estate Properties
Blanket mortgage on assets		$ 20,100,000
BRT Equity				14,026,000			4,410,000	6,220,000	3,396,000
Number of units in multi-family residential property				884			208	464	212
Contract Purchase price	57,400,000		57,400,000	57,400,000			21,500,000	25,450,000	10,450,000
Interest in joint venture (as a percent)					80.00%	90.00%
Acquisition Mortgage debt				45,010,000			17,716,000	19,248,000	8,046,000
Property acquisition costs	$ 878,000			$ 830,000			$ 213,000	$ 386,000	$ 231,000