Note 8 - Investment Securities - Investments by Contractual Maturity Date (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Due in one year or less, Amortized Cost	$ 124,789
Due in one year or less, Fair Value	124,794
Due after one year through five years, Amortized Cost	126,637
Due after one year through five years, Fair Value	117,089
Due after five years through ten years, Amortized Cost	142,206
Due after five years through ten years, Fair Value	141,424
Due after ten years, Amortized Cost	891,231
Due after ten years, Fair Value	836,234
Total, Amortized Cost	1,284,863	$ 1,126,867
Total, Fair Value	$ 1,219,541	$ 1,127,309