Note 5 - Assets Held for Rent (Details Textual) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Assets Held for Rent, Depreciation	$ 299,000	$ 267,000	$ 483,000	$ 395,000