Note 4 - Debt Securities Available-for-Sale (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Schedule Of Available For Sale Securities [Line Items]
Investment securities available-for-sale, debt securities	$ 692,360	$ 435,646
Investment securities available-for-sale, debt securities gross unrealized holding gains	3,568	7,514
Investment securities available-for-sale, debt securities gross unrealized holding losses	(8,302)	(363)
Investment securities available-for-sale, debt securities amortized cost	697,094	428,495
US Government Agencies Debt Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Investment securities available-for-sale, debt securities	97,499	69,776
Investment securities available-for-sale, debt securities gross unrealized holding gains	2	26
Investment securities available-for-sale, debt securities gross unrealized holding losses	(2,435)	(246)
Investment securities available-for-sale, debt securities amortized cost	99,932	69,996
US States and Political Subdivisions Debt Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Investment securities available-for-sale, debt securities	131,035	87,812
Investment securities available-for-sale, debt securities gross unrealized holding gains	1,716	2,350
Investment securities available-for-sale, debt securities gross unrealized holding losses	(1,053)	(45)
Investment securities available-for-sale, debt securities amortized cost	130,372	85,507
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	329,938	175,847
Investment securities available-for-sale, debt securities gross unrealized holding gains	1,273	3,328
Investment securities available-for-sale, debt securities gross unrealized holding losses	(3,158)	(24)
Investment securities available-for-sale, debt securities amortized cost	331,823	172,543
Collateralized Mortgage Obligations [Member]
Schedule Of Available For Sale Securities [Line Items]
Investment securities available-for-sale, debt securities	127,012	94,948
Investment securities available-for-sale, debt securities gross unrealized holding gains	398	1,751
Investment securities available-for-sale, debt securities gross unrealized holding losses	(1,648)	(5)
Investment securities available-for-sale, debt securities amortized cost	128,262	93,202
Collateralized Debt Obligations [Member]
Schedule Of Available For Sale Securities [Line Items]
Investment securities available-for-sale, debt securities	75	70
Investment securities available-for-sale, debt securities gross unrealized holding losses	(8)	(14)
Investment securities available-for-sale, debt securities amortized cost	83	84
Corporate Debt Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Investment securities available-for-sale, debt securities	6,801	7,193
Investment securities available-for-sale, debt securities gross unrealized holding gains	179	59
Investment securities available-for-sale, debt securities gross unrealized holding losses		(29)
Investment securities available-for-sale, debt securities amortized cost	$ 6,622	$ 7,163

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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