Note 3 - Investment Securities Available for Sale - Investment Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Jun. 30, 2026	Dec. 31, 2025
Within one year, amortized cost	$ 935
Within one year, fair value	934
After one year through five years, amortized cost	8,086
After one year through five years, estimated fair value	8,145
After five years through ten years, amortized cost	15,287
After five years through ten years, estimated fair value	15,370
After ten years, amortized cost	67,832
After ten years, estimated fair value	64,471
Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, before Allowance for Credit Loss	485,273	$ 491,490
Debt Securities, Available-for-Sale, Excluding Accrued Interest	465,991	476,595
Residential Mortgage Backed Securities Issued by US Government Sponsored Enterprises [Member]
Investment securities not due at a single maturity date, amortized cost	242,548
Investment securities not due at a single maturity date, estimated fair value	234,965
Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, before Allowance for Credit Loss	242,548	257,520
Debt Securities, Available-for-Sale, Excluding Accrued Interest	234,965	253,165
Commercial Mortgage Backed Securities Issued by US Government Agencies [Member]
Investment securities not due at a single maturity date, amortized cost	150,585
Investment securities not due at a single maturity date, estimated fair value	142,106
Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, before Allowance for Credit Loss	150,585	141,861
Debt Securities, Available-for-Sale, Excluding Accrued Interest	$ 142,106	$ 134,764

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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