Note 9 - Deposits (Details Textual) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Deposit Liabilities, Accrued Interest	$ 28.6	$ 13.2	$ 1.7
Geographic Distribution, Domestic [Member]
Time Deposits, at or Above FDIC Insurance Limit	5,300.0	4,100.0
Geographic Distribution, Foreign [Member]
Time Deposits, at or Above FDIC Insurance Limit	$ 174.2	$ 128.6