Investment in Unconsolidated Ventures - Balance Sheet Information (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022
ASSETS
Real estate properties, net of accumulated depreciation of $78,684 and $69,970	$ 621,379			$ 635,836
Cash and cash equivalents	45,801			23,512	$ 28,117
Other assets	18,988			15,741
Total Assets	717,741			709,963
Liabilities:
Mortgages payable, net of deferred costs of $912 and $1,135	447,147			422,427
Accounts payable and accrued liabilities	23,669			21,948
Total Liabilities	507,974			481,518
Commitments and contingencies
Equity:
Total unconsolidated joint venture equity	209,767	$ 214,674	$ 220,614	228,445	$ 236,797	$ 245,746	$ 243,334	$ 250,070
Total Liabilities and Equity	717,741			709,963
Real estate accumulated depreciation	99,899			80,499
Deferred costs	4,496			4,266
Asset under Construction
ASSETS
Real estate properties, net of accumulated depreciation of $78,684 and $69,970				46,508
Unconsolidated Joint Ventures
ASSETS
Real estate properties, net of accumulated depreciation of $78,684 and $69,970	320,839			275,874
Cash and cash equivalents	6,104			6,447
Other assets	8,951			54,715
Total Assets	335,894			337,036
Liabilities:
Mortgages payable, net of deferred costs of $912 and $1,135	251,982			246,966
Accounts payable and accrued liabilities	9,046			8,751
Total Liabilities	261,028			255,717
Commitments and contingencies
Equity:
Total unconsolidated joint venture equity	74,866			81,319
Total Liabilities and Equity	335,894			337,036
BRT's interest in joint venture equity	31,573			34,242
Real estate accumulated depreciation	78,684			69,970
Unconsolidated Joint Ventures | Mortgages payable
Equity:
Deferred costs	$ 912			$ 1,135