Note 4 - Investment Securities - Summary of Amortized Cost and Fair Value by Contractual Maturity (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Due in one year or less	$ 0
Due in one year or less	0
Due after one year through five years	9,818
Due after one year through five years	9,182
Due after five years through ten years	74,339
Due after five years through ten years	66,907
Due after ten years	138,955
Due after ten years	118,162
Total held-to-maturity securities	223,112
Total held-to-maturity securities	194,251
Due in one year or less	0
Due in one year or less	0
Due after one year through five years	20,963
Due after one year through five years	18,959
Due after five years through ten years	37,944
Due after five years through ten years	32,248
Due after ten years	146,619
Due after ten years	129,732
MBS - GSE residential, amortized cost	243,942
MBS - GSE residential, fair value	210,475
Total available-for-sale debt securities, amortized cost	449,468	$ 488,741
Total available-for-sale debt securities, fair value	$ 391,414	$ 420,862