Note 6 - Available-for-Sale (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Schedule Of Available For Sale Securities [Line Items]
Investment securities available-for-sale, debt securities	$ 537,904	$ 546,525
Investment securities available-for-sale, debt securities gross unrealized holding gains		2
Investment securities available-for-sale, debt securities gross unrealized holding losses	(91,283)	(102,694)
Investment securities available-for-sale, debt securities amortized cost	629,187	649,217
US Treasury Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Investment securities available-for-sale, debt securities		301
Investment securities available-for-sale, debt securities gross unrealized holding gains		2
Investment securities available-for-sale, debt securities amortized cost		299
US Government Agencies Debt Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Investment securities available-for-sale, debt securities	88,701	86,709
Investment securities available-for-sale, debt securities gross unrealized holding losses	(13,243)	(15,233)
Investment securities available-for-sale, debt securities amortized cost	101,944	101,942
US States and Political Subdivisions Debt Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Investment securities available-for-sale, debt securities	89,917	95,367
Investment securities available-for-sale, debt securities gross unrealized holding losses	(19,514)	(23,494)
Investment securities available-for-sale, debt securities amortized cost	109,431	118,861
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Schedule Of Available For Sale Securities [Line Items]
Investment securities available-for-sale, debt securities	252,984	256,161
Investment securities available-for-sale, debt securities gross unrealized holding losses	(41,314)	(45,303)
Investment securities available-for-sale, debt securities amortized cost	294,298	301,464
Collateralized Mortgage Obligations [Member]
Schedule Of Available For Sale Securities [Line Items]
Investment securities available-for-sale, debt securities	100,083	101,672
Investment securities available-for-sale, debt securities gross unrealized holding losses	(16,800)	(18,338)
Investment securities available-for-sale, debt securities amortized cost	116,883	120,010
Corporate Debt Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Investment securities available-for-sale, debt securities	6,219	6,315
Investment securities available-for-sale, debt securities gross unrealized holding losses	(412)	(326)
Investment securities available-for-sale, debt securities amortized cost	$ 6,631	$ 6,641

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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