Note 12 - Leases (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Operating Lease, Weighted Average Remaining Lease Term (Year)	30 years	37 months
Operating Lease, Weighted Average Discount Rate, Percent	2.10%	2.40%
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	$ 88,000	$ 533,000
Operating Lease, Payments	591,000	579,000
Other Operating Income (Expense) [Member]
Operating Lease, Cost	3,000,000.0	1,900,000
Short-term Lease, Cost	$ 2,400,000	$ 1,300,000
Minimum [Member]
Lessee, Operating Lease, Renewal Term (Month)	6 months
Maximum [Member]
Lessee, Operating Lease, Renewal Term (Month)	3 years