Note 3 - Securities - Available-for-sale Debt Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Available-for-sale debt securities, amortized cost	$ 493,360	$ 501,402
Available-for-sale debt securities, gross unrealized holding gains	215	201
Available-for-sale debt securities, gross unrealized holding losses	51,455	50,789
Available-for-sale debt securities, at fair value	442,120	450,814
US Treasury Securities [Member]
Available-for-sale debt securities, amortized cost	36,864	36,852
Available-for-sale debt securities, gross unrealized holding gains	0	0
Available-for-sale debt securities, gross unrealized holding losses	3,950	3,675
Available-for-sale debt securities, at fair value	32,914	33,177
US States and Political Subdivisions Debt Securities [Member]
Available-for-sale debt securities, amortized cost	217,185	220,181
Available-for-sale debt securities, gross unrealized holding gains	25	52
Available-for-sale debt securities, gross unrealized holding losses	21,470	20,437
Available-for-sale debt securities, at fair value	195,740	199,796
Residential Mortgage-Backed Securities [Member]
Available-for-sale debt securities, amortized cost	85,865	87,405
Available-for-sale debt securities, gross unrealized holding gains	0	0
Available-for-sale debt securities, gross unrealized holding losses	13,062	13,198
Available-for-sale debt securities, at fair value	72,803	74,207
Commercial Mortgage-Backed Securities [Member]
Available-for-sale debt securities, amortized cost	3,604	3,613
Available-for-sale debt securities, gross unrealized holding gains	0	0
Available-for-sale debt securities, gross unrealized holding losses	234	227
Available-for-sale debt securities, at fair value	3,370	3,386
Collateralized Mortgage-Backed Securities [Member]
Available-for-sale debt securities, amortized cost	18,241	18,872
Available-for-sale debt securities, gross unrealized holding gains	2	4
Available-for-sale debt securities, gross unrealized holding losses	2,712	2,430
Available-for-sale debt securities, at fair value	15,531	16,446
Mortgage-Backed Securities, Issued by Private Enterprises [Member]
Available-for-sale debt securities, amortized cost	72,680	76,912
Available-for-sale debt securities, gross unrealized holding gains	54	78
Available-for-sale debt securities, gross unrealized holding losses	6,432	6,838
Available-for-sale debt securities, at fair value	66,302	70,152
Corporate Debt Securities [Member]
Available-for-sale debt securities, amortized cost	35,050	35,055
Available-for-sale debt securities, gross unrealized holding gains	0	0
Available-for-sale debt securities, gross unrealized holding losses	3,486	3,769
Available-for-sale debt securities, at fair value	31,564	31,286
Asset-Backed Securities [Member]
Available-for-sale debt securities, amortized cost	23,127	21,768
Available-for-sale debt securities, gross unrealized holding gains	134	67
Available-for-sale debt securities, gross unrealized holding losses	47	145
Available-for-sale debt securities, at fair value	23,214	21,690
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	62	70
Available-for-sale debt securities, at fair value	$ 682	$ 674

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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