Note 2 - Securities - Amortized Cost and Estimated Fair Value of Investment Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Investment securities available for sale, amortized cost	$ 341,011	$ 333,950
Investment securities available for sale, at fair value (amortized cost of $341,011 and $333,950, respectively)	310,860	295,623
Collateralized Mortgage-Backed Securities [Member]
Due within one year, amortized cost	19,249	25,279
Due within one year, estimated fair value	19,091	25,017
Due after one through five years, amortized cost	4,264	16,622
Due after one through five years, estimated fair value	4,226	16,029
Due after five through ten years, amortized cost	8,141	8,874
Due after five through ten years, estimated fair value	7,782	8,197
Due after ten years, amortized cost	118,709	106,445
Due after ten years, estimated fair value	105,336	90,097
Investment securities available for sale, amortized cost	150,363	157,220
Investment securities available for sale, at fair value (amortized cost of $341,011 and $333,950, respectively)	136,435	139,340
Investment Securities, Excluding Mortgage Backed Securities [Member]
Due within one year, amortized cost	1,000	300
Due within one year, estimated fair value	815	300
Due after one through five years, amortized cost	20,574	18,187
Due after one through five years, estimated fair value	19,857	17,384
Due after five through ten years, amortized cost	53,073	57,328
Due after five through ten years, estimated fair value	48,893	50,768
Due after ten years, amortized cost	116,001	100,915
Due after ten years, estimated fair value	104,860	87,831
Investment securities available for sale, amortized cost	190,648	176,730
Investment securities available for sale, at fair value (amortized cost of $341,011 and $333,950, respectively)	$ 174,425	$ 156,283