Note 5 - Deferred Costs and Intangible Assets (Details Textual) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Amortization of Lease Origination Costs and In-place Lease Intangible Assets		$ 693	$ 1,240	$ 1,182
Write off of Fully Amortized Lease Origination Costs and In-place Leases		8,994
Amortization of Real Estate Abatements		482	475	1,568
Write off of Fully Amortized Real Estate Tax Abatements		3,428
Amortization of Intangible Assets, Total		$ 118	$ 235	$ 58
Above Market Leases [Member]
Impairment of Intangible Assets, Finite-lived	$ 36