Investment in Unconsolidated Ventures - Income Statement Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Revenues:
Rental and other revenue	$ 7,709	$ 7,020	$ 21,762	$ 20,422
Total revenues	7,714	7,313	21,774	21,053
Expenses:
Real estate operating expenses	3,404	3,289	9,687	9,351
Interest expense	1,535	1,731	4,804	5,400
Depreciation	1,787	1,777	4,740	5,147
Total expenses	9,840	13,169	29,133	32,594
Total revenues less total expenses	(2,126)	(5,856)	(7,359)	(11,541)
Impairment of assets	0	(3,642)	(520)	(3,642)
Gain on sale of real estate	414	0	7,693	0
Loss on extinguishment of debt	(902)	0	(902)	0
Net income (loss) from joint ventures	35	34	102	97
BRT's equity in loss and equity in earnings from sale of unconsolidated joint venture properties	28,106	(7,484)	30,368	(16,561)
Unconsolidated Joint Ventures
Revenues:
Rental and other revenue	29,818	32,341	95,495	94,726
Total revenues	29,818	32,341	95,495	94,726
Expenses:
Real estate operating expenses	14,587	16,092	45,523	45,298
Interest expense	7,568	8,663	24,562	26,186
Depreciation	8,288	10,411	28,464	31,184
Total expenses	30,443	35,166	98,549	102,668
Total revenues less total expenses	(625)	(2,825)	(3,054)	(7,942)
Other equity earnings	7	97	21	34
Impairment of assets	0	0	(2,813)	0
Insurance recoveries	0	0	2,813	0
Gain on insurance recoveries	1,246	427	1,246	765
Gain on sale of real estate	83,984	0	83,984	0
Loss on extinguishment of debt	(9,401)	0	(9,401)	0
Net income (loss) from joint ventures	75,211	(2,301)	72,796	(7,143)
BRT's equity in loss and equity in earnings from sale of unconsolidated joint venture properties	$ 30,786	$ (1,529)	$ 28,949	$ (4,731)