Note 6 - Available-for-Sale (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Schedule Of Available For Sale Securities [Line Items]
Investment securities available-for-sale, debt securities	$ 656,846	$ 692,360
Investment securities available-for-sale, debt securities gross unrealized holding gains	272	3,568
Investment securities available-for-sale, debt securities gross unrealized holding losses	(51,337)	(8,302)
Investment securities available-for-sale, debt securities amortized cost	707,911	697,094
US Treasury Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Investment securities available-for-sale, debt securities	894
Investment securities available-for-sale, debt securities amortized cost	894
US Government Agencies Debt Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Investment securities available-for-sale, debt securities	94,063	97,499
Investment securities available-for-sale, debt securities gross unrealized holding gains		2
Investment securities available-for-sale, debt securities gross unrealized holding losses	(7,872)	(2,435)
Investment securities available-for-sale, debt securities amortized cost	101,935	99,932
US States and Political Subdivisions Debt Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Investment securities available-for-sale, debt securities	119,510	131,035
Investment securities available-for-sale, debt securities gross unrealized holding gains	139	1,716
Investment securities available-for-sale, debt securities gross unrealized holding losses	(12,427)	(1,053)
Investment securities available-for-sale, debt securities amortized cost	131,798	130,372
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	308,225	329,938
Investment securities available-for-sale, debt securities gross unrealized holding gains	59	1,273
Investment securities available-for-sale, debt securities gross unrealized holding losses	(22,699)	(3,158)
Investment securities available-for-sale, debt securities amortized cost	330,865	331,823
Collateralized Mortgage Obligations [Member]
Schedule Of Available For Sale Securities [Line Items]
Investment securities available-for-sale, debt securities	127,534	127,012
Investment securities available-for-sale, debt securities gross unrealized holding gains	8	398
Investment securities available-for-sale, debt securities gross unrealized holding losses	(8,198)	(1,648)
Investment securities available-for-sale, debt securities amortized cost	135,724	128,262
Corporate Debt Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Investment securities available-for-sale, debt securities	6,620	6,876
Investment securities available-for-sale, debt securities gross unrealized holding gains	66	179
Investment securities available-for-sale, debt securities gross unrealized holding losses	(141)	(8)
Investment securities available-for-sale, debt securities amortized cost	$ 6,695	$ 6,705

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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