Note 6 - Leases (Details Textual) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Lessee, Operating Lease, Remaining Lease Term (Year)	10 years		10 years
Operating Lease, Right-of-Use Asset	$ 20.5		$ 20.5		$ 18.8
Operating Lease, Liability	$ 21.4		$ 21.4		$ 19.6
Operating Lease, Weighted Average Remaining Lease Term (Year)	6 years		6 years
Operating Lease, Weighted Average Discount Rate, Percent	3.16%		3.16%
Operating Lease, Payments	$ 1.8	$ 1.1	$ 4.3	$ 3.1