Note 4 - Investment Securities - Schedule of Investments Classified by Contractual Maturity Date (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Due within one year or less, Held-to-maturity, Amortized Cost	$ 8,282
Due within one year or less, Held-to-maturity, Fair Value	8,203
Due within one year or less, Available-for-sale, Amortized Cost	0
Due within one year or less, Available-for-sale, Fair Value	0
Due after one year through five years, Held-to-maturity, Amortized Cost	56,385
Due after one year through five years, Held-to-maturity, Fair Value	53,122
Due after one year through five years, Available-for-sale, Amortized Cost	1,838
Due after one year through five years, Available-for-sale, Fair Value	1,778
Due after five years through ten years, Held-to-maturity, Amortized Cost	48,042
Due after five years through ten years, Held-to-maturity, Fair Value	43,323
Due after five years through ten years, Available-for-sale, Amortized Cost	57,992
Due after five years through ten years, Available-for-sale, Fair Value	49,460
Due after 10 years, Held-to-maturity, Amortized Cost	10,008
Due after 10 years, Held-to-maturity, Fair Value	8,945
Due after 10 years, Available-for-sale, Amortized Cost	377
Due after 10 years, Available-for-sale, Fair Value	377
Held-to-maturity, Amortized Cost	122,717
Held-to-maturity, Fair Value	113,593
Available-for-sale, Amortized Cost	60,207
Available-for-sale, Fair Value	51,615
Total investment securities	282,050
Total investment securities, Held-to-maturity, Fair Value	249,862	$ 258,617
Total investment securities, Available-for-sale, Amortized Cost	549,122
Total investment securities, Available-for-sale, Fair Value	466,003	486,736
Residential Mortgage-Backed Securities [Member]
Residential agency, Held-to-maturity, Amortized Cost	159,333
Residential agency, Held-to-maturity, Fair Value	136,269
Residential agency, Available-for-sale, Amortized Cost	488,915
Residential agency, Available-for-sale, Fair Value	414,388
Total investment securities, Held-to-maturity, Fair Value	136,269	141,627
Total investment securities, Available-for-sale, Fair Value	$ 414,388	$ 435,594