Note 3 - Investment Securities - Investments by Contractual Maturity Date (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Due in one year or less, Amortized Cost	$ 5,005
Due in one year or less, Fair Value	5,009
Due after one year through five years, Amortized Cost	126,871
Due after one year through five years, Fair Value	124,148
Due after five years through ten years, Amortized Cost	137,989
Due after five years through ten years, Fair Value	141,331
Due after ten years, Amortized Cost	857,002
Due after ten years, Fair Value	856,821
Total, Amortized Cost	1,126,867	$ 1,019,230
Total, Fair Value	$ 1,127,309	$ 1,036,550