Note 8 - Lease Revenue (Details Textual) - USD ($)		3 Months Ended		9 Months Ended
	Jan. 01, 2019	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 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		$ 8,668,344	$ 9,148,865	$ 26,967,569	$ 26,895,382
CAM Lease Revenue Billed [Member]
Revenue from Contract with Customer, Excluding Assessed Tax, Total				$ 358,600	$ 305,100
Minimum [Member]
Operating Lease, Lease Income, Lease Payments	$ 193,000
Maximum [Member]
Operating Lease, Lease Income, Lease Payments	$ 410,000