Note 8 - Lease Revenue (Details Textual) - USD ($)		3 Months Ended
	Jan. 01, 2019	Mar. 31, 2020	Mar. 31, 2019
Lessor, Operating Lease, Term of Contract (Year)	7 years
Lessor, Operating Lease, Renewal Term (Year)	5 years
Revenue from Contract with Customer, Excluding Assessed Tax, Total		$ 10,282,665	$ 9,489,504
CAM Lease Revenue Billed [Member]
Revenue from Contract with Customer, Excluding Assessed Tax, Total		$ 89,000	$ 72,000
Minimum [Member]
Operating Lease, Lease Income, Lease Payments	$ 193,000
Maximum [Member]
Operating Lease, Lease Income, Lease Payments	$ 410,000