Note 4 - Intangible Assets (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Impairment of Intangible Assets (Excluding Goodwill), Total	$ 0	$ 0	$ 0
Favorable Lease Rates [Member] | Minimum [Member]
Finite-Lived Intangible Asset, Useful Life	41 years
Favorable Lease Rates [Member] | Maximum [Member]
Finite-Lived Intangible Asset, Useful Life	52 years
Customer Relationships [Member]
Finite-Lived Intangible Asset, Useful Life	3 years 6 months	7 years 3 months 18 days
Finite-Lived Intangible Asset, Original Life	5 years
Host Relationships [Member]
Finite-Lived Intangible Asset, Useful Life	15 years