INVESTMENT IN UNCONSOLIDATED VENTURES - Income Statement Information (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020
Revenues:
Rental and other revenue	$ 10,279	$ 7,709	$ 6,958	$ 7,095	$ 7,029	$ 7,020	$ 6,657	$ 6,745	$ 32,041	$ 27,451
Total revenues	10,283	7,714	6,961	7,099	7,049	7,313	6,816	6,924	32,057	28,102
Expenses:
Real estate operating expenses	4,515	3,404	3,166	3,117	3,026	3,289	3,004	3,058	14,202	12,377
Interest expense	1,953	1,535	1,609	1,660	1,700	1,731	1,809	1,860	6,757	7,100
Depreciation	3,285	1,787	1,416	1,537	1,595	1,777	1,809	1,561	8,025	6,742
Total expenses	12,992	9,840	9,865	9,428	8,968	13,169	9,579	9,846	42,125	41,562
Total revenues less total expenses	(2,709)	(2,126)	(2,904)	(2,329)	(1,919)	(5,856)	(2,763)	(2,922)	(10,068)	(13,460)
Impairment of assets	0	0	(520)	0	0	(3,642)	0	0	(520)	(3,642)
Gain on sale of real estate	0	414	7,279	0	0	0	0	0	7,693	0
Loss on extinguishment of debt	(673)	(902)	0	0	0	0	0	0	(1,575)	0
Net income (loss) attributable to common stockholders	$ (1,254)	$ 28,106	$ 6,027	$ (3,765)	$ (3,301)	$ (7,484)	$ (4,246)	$ (4,831)	29,114	(19,862)
BRT equity in loss and equity in earnings from sale of unconsolidated joint venture properties									30,774	(6,024)
Unconsolidated joint ventures
Revenues:
Rental and other revenue									121,906	127,058
Total revenues									121,906	127,058
Expenses:
Real estate operating expenses									56,507	60,326
Interest expense									30,964	34,918
Depreciation									35,636	41,657
Total expenses									123,107	136,901
Total revenues less total expenses									(1,201)	(9,843)
Other equity earnings									54	117
Impairment of assets									(2,813)	0
Insurance recoveries									2,813	0
Gain on insurance recoveries									2,179	765
Gain on sale of real estate									83,984	0
Loss on extinguishment of debt									(9,401)	0
Net income (loss) attributable to common stockholders									$ 75,615	$ (8,961)