Note 8 - Investment Securities - Investments by Contractual Maturity Date (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Due in one year or less, Amortized Cost	$ 139,838
Due in one year or less, Fair Value	138,315
Due after one year through five years, Amortized Cost	146,693
Due after one year through five years, Fair Value	135,240
Due after five years through ten years, Amortized Cost	147,294
Due after five years through ten years, Fair Value	144,903
Due after ten years, Amortized Cost	902,468
Due after ten years, Fair Value	816,113
Total, Amortized Cost	1,336,293	$ 1,126,867
Total, Fair Value	$ 1,234,571	$ 1,127,309