Note 6 - Mortgage and Other Indebtedness - Schedule of Debt Balance (Parenthetical) (Details) - USD ($) $ in Thousands				1 Months Ended			9 Months Ended		12 Months Ended
		Jun. 16, 2020	Dec. 27, 2019	Jul. 31, 2021	Jun. 30, 2020	Dec. 31, 2019	Sep. 30, 2021		Dec. 31, 2020		Mar. 31, 2021
Debt Instrument [Line Items]
Debt instrument net of discount							$ 1,100		$ 900
Balance outstanding							$ 159,441
MVB Revolver [Member]
Debt Instrument [Line Items]
Interest Rate	[1]						6.75%		6.75%
Maturity date							Dec. 27, 2021		Dec. 27, 2021
Sub-OP [Member]
Debt Instrument [Line Items]
Preferred investor, additional capital contribution		$ 2,900			$ 2,900
Preferred investor, additional capital contribution outstanding							$ 1,900
LIBOR [Member]
Debt Instrument [Line Items]
Debt instrument variable rate							0.08%
Prime Rate [Member] | MVB Revolver [Member]
Debt Instrument [Line Items]
Debt instrument variable rate							1.50%
Interest Rate Swap [Member] | Hollinswood Loan [Member]
Debt Instrument [Line Items]
Interest Rate							4.06%
Basis Term Loan [Member]
Debt Instrument [Line Items]
Debt instrument net of discount							$ 466		$ 745
Interest Rate						6.125%	6.125%	[1]	6.125%	[1]
Balance outstanding							$ 66,900
Maturity date						Jan. 01, 2023	Jan. 01, 2023		Jan. 01, 2023
Basis Term Loan [Member] | Sub-OP [Member]
Debt Instrument [Line Items]
Preferred investor, additional capital contribution		2,400
Basis Term Loan [Member] | Interest Rate Cap [Member]
Debt Instrument [Line Items]
Debt instrument variable rate			6.125%
Basis Term Loan [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Debt instrument variable rate						3.85%	3.85%
Basis Term Loan [Member] | LIBOR [Member] | Interest Rate Cap [Member]
Debt Instrument [Line Items]
Debt instrument variable rate			3.85%				3.50%
Basis Preferred Interest [Member]
Debt Instrument [Line Items]
Debt instrument net of discount							$ 94		$ 150
Interest Rate	[1],[2],[3]						14.00%		14.00%
Maturity date	[3],[4]						Jan. 01, 2023		Jan. 01, 2023
Vista Shops at Golden Mile Loan [Member]
Debt Instrument [Line Items]
Debt instrument net of discount							$ 45		$ 0
Interest Rate							3.83%	[1],[5]	3.83%	[1],[5]	3.83%
Maturity date	[5]						Jun. 24, 2023		Jun. 24, 2023
Vista Shops at Golden Mile Loan [Member] | Mortgage Loan [Member]
Debt Instrument [Line Items]
Maturity date							Jan. 25, 2021
Vista Shops at Golden Mile Loan [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Debt instrument variable rate							2.50%
Lamar Station Plaza East Loan [Member]
Debt Instrument [Line Items]
Debt instrument net of discount							$ 12		$ 7
Interest Rate	[1]						4.00%		4.00%
Maturity date	[6]						Jul. 17, 2022		Jul. 17, 2022
Lamar Station Plaza East Loan [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Debt instrument variable rate							3.00%		3.00%
Lamar Station Plaza East Loan [Member] | LIBOR [Member] | Minimum [Member]
Debt Instrument [Line Items]
Debt instrument variable rate							1.00%
Cromwell Land Loan [Member]
Debt Instrument [Line Items]
Debt instrument net of discount							$ 0		$ 10
Interest Rate	[1],[7]								6.75%
Maturity date	[7]						Jan. 10, 2023		Jan. 10, 2023
Lamont Street Preferred Interest [Member]
Debt Instrument [Line Items]
Debt instrument net of discount							$ 76
Interest Rate	[1],[8]						13.50%
Maturity date	[8]						Sep. 30, 2023
Highlandtown Village Shopping Center Loan [Member]
Debt Instrument [Line Items]
Debt instrument net of discount							$ 54
Interest Rate	[1]						4.13%
Maturity date							May 06, 2023
Cromwell Field Shopping Center Loan [Member]
Debt Instrument [Line Items]
Debt instrument net of discount							$ 185
Interest Rate	[1]						5.90%
Maturity date	[8]						Nov. 15, 2022
Cromwell Field Shopping Center Loan [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Debt instrument variable rate							5.40%
Cromwell Field Shopping Center Loan [Member] | LIBOR [Member] | Minimum [Member]
Debt Instrument [Line Items]
Debt instrument variable rate							0.50%
Cromwell Field Shopping Center Mezzanine Loan [Member]
Debt Instrument [Line Items]
Debt instrument net of discount							$ 23
Interest Rate	[1]						10.00%
Maturity date							Nov. 15, 2022
Spotswood Valley Square Shopping Center Loan [Member]
Debt Instrument [Line Items]
Debt instrument net of discount							$ 110
Interest Rate	[1]						4.82%
Maturity date							Jul. 06, 2023
Hollinswood Loan [Member]
Debt Instrument [Line Items]
Interest Rate	[1]						4.06%		4.06%
Maturity date							Dec. 01, 2024		Dec. 01, 2024
Hollinswood Loan [Member] | Interest Rate Cap [Member]
Debt Instrument [Line Items]
Debt instrument variable rate			4.06%
Hollinswood Loan [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Debt instrument variable rate							2.25%		2.25%
Brookhill Azalea Shopping Center Loan [Member]
Debt Instrument [Line Items]
Interest Rate	[1]						2.83%		2.85%
Maturity date							Jan. 31, 2025		Jan. 31, 2025
Brookhill Azalea Shopping Center Loan [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Debt instrument variable rate							2.75%		2.75%
Basis Preferred Interest Minimum Multiple Amount [Member]
Debt Instrument [Line Items]
Balance outstanding							$ 1,000		$ 1,800
Basis Preferred Interest Minimum Multiple Amount [Member] | Sub-OP [Member]
Debt Instrument [Line Items]
Balance outstanding							1,000
Other Capital Contribution [Member] | Sub-OP [Member]
Debt Instrument [Line Items]
Preferred investor, additional capital contribution		$ 500
Preferred units, cumulative annual return		13.00%			13.00%
Lamar Station Plaza East [Member]
Debt Instrument [Line Items]
Maturity date				Jul. 31, 2022
Lamont Street Minimum Multiple Amount [Member]
Debt Instrument [Line Items]
Balance outstanding							$ 800

[1] For floating rate loans tied to LIBOR, based on the one-month LIBOR rate of 0.08%, as of September 30, 2021.

[2] In June 2020, the Preferred Investor made additional capital contributions of approximately $2.9 million as described below under the heading “—Basis Preferred Interest” of which approximately $1.9 million was outstanding at September 30, 2021. The Preferred Investor is entitled to a cumulative annual return of 13.0% on the additional contributions.

[3] The outstanding balance includes approximately $1.0 million and $1.8 million of indebtedness as of September 30, 2021 and December 31, 2020, respectively, related to the Multiple Minimum Amount owed to the Preferred Investor as described below under the heading “—Basis Preferred Interest”.

[4] If the Basis Term Loan is paid in full earlier than its maturity date, the Basis Preferred Interest in the Sub-OP (as defined below) will mature at that time.

[5] The Company completed the refinance of this loan in March 2021 as described below under the heading “—Mortgage Indebtedness”. The prior loan matured on January 25, 2021 and carried an interest rate of LIBOR plus 2.5% per annum.

[6] In July 2021, the Company entered into a modification to the Lamar Station Plaza East loan to extend the maturity date to July 2022 as described below under the heading “—Mortgage Indebtedness”.

[7] The Company paid off the remaining principal balance of the Cromwell land loan during the second quarter of 2021.

[8] The outstanding balance includes approximately $0.8 million of indebtedness as of September 30, 2021 related to the Lamont Street Minimum Multiple Amount owed to Lamont Street as described below under the heading “—Lamont Street Preferred Interest”.