Note 5 - Leasing Arrangements - Rental Income under Operating Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Minimum rentals	$ 2,719	$ 2,863
Percentage rentals	427	1,779
Licensing fees	456	912
Other (primarily common area recoveries)	1,236	1,353
Leasing	5,948	8,148
Water System Sales [Member]
Leasing	$ 1,110	$ 1,241