Note 3 - Securities - Available-for-sale Debt Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Available-for-sale debt securities, amortized cost	$ 537,912	$ 514,801
Available-for-sale debt securities, gross unrealized holding gains	96	12,202
Available-for-sale debt securities, gross unrealized holding losses	61,917	4,437
Available-for-sale debt securities	476,091	522,566
US Treasury Securities [Member]
Available-for-sale debt securities, amortized cost	36,801	36,751
Available-for-sale debt securities, gross unrealized holding gains	0	1
Available-for-sale debt securities, gross unrealized holding losses	4,667	397
Available-for-sale debt securities	32,134	36,355
US States and Political Subdivisions Debt Securities [Member]
Available-for-sale debt securities, amortized cost	250,244	235,489
Available-for-sale debt securities, gross unrealized holding gains	90	9,651
Available-for-sale debt securities, gross unrealized holding losses	29,552	768
Available-for-sale debt securities	220,782	244,372
Residential Mortgage-Backed Securities [Member]
Available-for-sale debt securities, amortized cost	93,577	101,321
Available-for-sale debt securities, gross unrealized holding gains	0	1,158
Available-for-sale debt securities, gross unrealized holding losses	13,170	1,769
Available-for-sale debt securities	80,407	100,710
Commercial Mortgage-Backed Securities [Member]
Available-for-sale debt securities, amortized cost	3,649	3,685
Available-for-sale debt securities, gross unrealized holding gains	0	87
Available-for-sale debt securities, gross unrealized holding losses	320	45
Available-for-sale debt securities	3,329	3,727
Collateralized Mortgage-Backed Securities [Member]
Available-for-sale debt securities, amortized cost	23,332	25,467
Available-for-sale debt securities, gross unrealized holding gains	1	263
Available-for-sale debt securities, gross unrealized holding losses	2,670	224
Available-for-sale debt securities	20,663	25,506
Mortgage-Backed Securities, Issued by Private Enterprises [Member]
Available-for-sale debt securities, amortized cost	80,648	68,137
Available-for-sale debt securities, gross unrealized holding gains	0	60
Available-for-sale debt securities, gross unrealized holding losses	8,141	1,032
Available-for-sale debt securities	72,507	67,165
Corporate Debt Securities [Member]
Available-for-sale debt securities, amortized cost	33,630	31,300
Available-for-sale debt securities, gross unrealized holding gains	0	940
Available-for-sale debt securities, gross unrealized holding losses	2,958	177
Available-for-sale debt securities	30,672	32,063
Asset-Backed Securities [Member]
Available-for-sale debt securities, amortized cost	15,287	11,907
Available-for-sale debt securities, gross unrealized holding gains	5	42
Available-for-sale debt securities, gross unrealized holding losses	351	17
Available-for-sale debt securities	14,941	11,932
Negotiable Certificates of Deposit [Member]
Available-for-sale debt securities, amortized cost	744	744
Available-for-sale debt securities, gross unrealized holding gains	0	0
Available-for-sale debt securities, gross unrealized holding losses	88	8
Available-for-sale debt securities	$ 656	$ 736

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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Amount, before tax, of unrealized loss 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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Amortized cost of 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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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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