Note 3 - Investment Securities Available for Sale - Investment Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Under one year, amortized cost	$ 735
Under one year, fair value	733
After one year through five years, amortized cost	6,072
After one year through five years, estimated fair value	6,087
After five years through ten years, amortized cost	19,749
After five years through ten years, estimated fair value	19,500
After ten years, amortized cost	71,391
After ten years, estimated fair value	61,591
Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, before Allowance for Credit Loss	469,031	$ 473,433
Debt Securities, Available-for-Sale, Excluding Accrued Interest	439,676	437,735
Residential Mortgage Backed Securities Issued by US Government Sponsored Enterprises [Member]
Investment securities not due at a single maturity date, amortized cost	232,554
Investment securities not due at a single maturity date, estimated fair value	222,524
Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, before Allowance for Credit Loss	232,554	243,709
Debt Securities, Available-for-Sale, Excluding Accrued Interest	222,524	228,391
Commercial Mortgage Backed Securities Issued by US Government Agencies [Member]
Investment securities not due at a single maturity date, amortized cost	138,530
Investment securities not due at a single maturity date, estimated fair value	129,241
Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, before Allowance for Credit Loss	138,530	133,749
Debt Securities, Available-for-Sale, Excluding Accrued Interest	$ 129,241	$ 121,870

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in sixth through tenth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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