Note 2 - Accounting Policies and Related Matters - Schedule of Depreciation and Amortization of Real Estate Assets and Liabilities (Details)	12 Months Ended
	Dec. 31, 2019
Building [Member] | Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Useful life	20 years
Building [Member] | Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Useful life	45 years
Improvements [Member] | Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Useful life	7 years 6 months
Improvements [Member] | Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Useful life	15 years
Lease Intangibles [Member] | Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Useful life	1 month
Lease Intangibles [Member] | Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Useful life	19 years