Note 6 - Mortgage and Other Indebtedness - Scheduled Principal Repayments and Maturities (Parenthetical) (Details) - USD ($) $ in Millions		1 Months Ended	6 Months Ended	12 Months Ended
		Jul. 31, 2021	Jun. 30, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Mortgages with principal balances outstanding			$ 3.5
Lamar Station Plaza East Loan [Member]
Debt Instrument [Line Items]
Mortgages with principal balances outstanding			$ 3.5
Maturity date	[1]		Jul. 17, 2022	Jul. 17, 2022
Subsequent Event [Member] | Lamar Station Plaza East Loan [Member]
Debt Instrument [Line Items]
Maturity date		Jul. 31, 2022

[1] 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”.