Note 1 - Organization (Details Textual) $ in Thousands	1 Months Ended			3 Months Ended
	Aug. 31, 2022 USD ($)	Apr. 30, 2022 USD ($)	Feb. 28, 2022 USD ($)	Mar. 31, 2023 USD ($) ft²	Mar. 31, 2022 USD ($)	Dec. 31, 2019
Payments to Acquire Real Estate | $				$ 12,494	$ 13,885
Percentage of Aggregate Cash Distributions From, and Profits and Losses				37.90%
Corporate Joint Venture [Member]
Joint Venture, Ownership Percentage						50.00%
Corporate Joint Venture [Member] | General and Administrative Expense [Member]
Joint Venture Expense | $				$ 0	$ 20
Land [Member]
Payments to Acquire Real Estate | $	$ 2,500	$ 4,300	$ 3,700
Tribeca House properties in Manhattan [Member]
Number of Buildings				2
Tribeca House properties in Manhattan [Member] | Residential Rental [Member]
Gross Leasable Area (Square Foot)				483,000
Tribeca House properties in Manhattan, Building One [Member]
Number of Stories				21
Tribeca House properties in Manhattan, Building One [Member] | Rental Retail and Parking [Member]
Gross Leasable Area (Square Foot)				77,000
Tribeca House properties in Manhattan, Building Two [Member]
Number of Stories				12
Flatbush Gardens, Brooklyn, NY [Member] | Multifamily [Member]
Number of Buildings				59
Gross Leasable Area (Square Foot)				1,749,000
Number of Rentable Units				2,494
141 Livingston Street in Brooklyn [Member] | Office Building [Member]
Number of Stories				15
Gross Leasable Area (Square Foot)				216,000
250 Livingston Street in Brooklyn [Member] | Office and Residential Building [Member]
Number of Stories				12
Gross Leasable Area (Square Foot)				370,000
Aspen [Member]
Number of Stories				7
Aspen [Member] | Residential Rental [Member]
Gross Leasable Area (Square Foot)				166,000
Aspen [Member] | Retail Site [Member]
Gross Leasable Area (Square Foot)				21,000
Clover House [Member]
Number of Stories				11
Clover House [Member] | Apartment Building [Member]
Gross Leasable Area (Square Foot)				102,000
Residential Property At 10 West 65th Street [Member] | Residential Rental [Member]
Number of Stories				6
Gross Leasable Area (Square Foot)				76,000
Residential Property At 1010 Pacific Street [Member] | Residential Rental [Member]
Number of Stories				9
Gross Leasable Area (Square Foot)				119,000
Dean Street, Prospect Heights [Member] | Residential Rental [Member]
Number of Stories				9
Gross Leasable Area (Square Foot)				160,000
Dean Street, Prospect Heights [Member] | Retail Site [Member]
Gross Leasable Area (Square Foot)				9,000