Note 6 - Available-for-Sale (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Schedule Of Available For Sale Securities [Line Items]
Investment securities available-for-sale, debt securities	$ 549,385	$ 435,646
Investment securities available-for-sale, debt securities gross unrealized holding gains	5,607	7,514
Investment securities available-for-sale, debt securities gross unrealized holding losses	(3,074)	(363)
Investment securities available-for-sale, debt securities amortized cost	546,852	428,495
US Government Agencies Debt Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Investment securities available-for-sale, debt securities	68,879	69,776
Investment securities available-for-sale, debt securities gross unrealized holding gains	15	26
Investment securities available-for-sale, debt securities gross unrealized holding losses	(1,084)	(246)
Investment securities available-for-sale, debt securities amortized cost	69,948	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	116,657	87,812
Investment securities available-for-sale, debt securities gross unrealized holding gains	1,939	2,350
Investment securities available-for-sale, debt securities gross unrealized holding losses	(688)	(45)
Investment securities available-for-sale, debt securities amortized cost	115,406	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	265,793	175,847
Investment securities available-for-sale, debt securities gross unrealized holding gains	2,204	3,328
Investment securities available-for-sale, debt securities gross unrealized holding losses	(1,055)	(24)
Investment securities available-for-sale, debt securities amortized cost	264,644	172,543
Collateralized Mortgage Obligations [Member]
Schedule Of Available For Sale Securities [Line Items]
Investment securities available-for-sale, debt securities	90,147	94,948
Investment securities available-for-sale, debt securities gross unrealized holding gains	1,254	1,751
Investment securities available-for-sale, debt securities gross unrealized holding losses	(235)	(5)
Investment securities available-for-sale, debt securities amortized cost	89,128	93,202
Collateralized Debt Obligations [Member]
Schedule Of Available For Sale Securities [Line Items]
Investment securities available-for-sale, debt securities	72	70
Investment securities available-for-sale, debt securities gross unrealized holding losses	(12)	(14)
Investment securities available-for-sale, debt securities amortized cost	84	84
Corporate Debt Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Investment securities available-for-sale, debt securities	7,837	7,193
Investment securities available-for-sale, debt securities gross unrealized holding gains	195	59
Investment securities available-for-sale, debt securities gross unrealized holding losses		(29)
Investment securities available-for-sale, debt securities amortized cost	$ 7,642	$ 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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