Note 3 - Securities - Amortized Cost and Estimated Fair Values of Debt Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Available-for-sale securities, amortized cost	$ 526,179	$ 545,274
Available-for-sale securities, gross unrealized gains	1,079	2,948
Available-for-sale securities, gross unrealized losses	(34,496)	(30,144)
Available-for-sale securities, fair market value	492,762	518,078
US Government Agencies Debt Securities [Member]
Available-for-sale securities, amortized cost	107,760	84,678
Available-for-sale securities, gross unrealized gains	8	11
Available-for-sale securities, gross unrealized losses	(5,658)	(4,430)
Available-for-sale securities, fair market value	102,110	80,259
Collateralized Mortgage Obligations [Member]
Available-for-sale securities, amortized cost	17,140	9,108
Available-for-sale securities, gross unrealized gains	7	0
Available-for-sale securities, gross unrealized losses	(556)	(444)
Available-for-sale securities, fair market value	16,591	8,664
US States and Political Subdivisions Debt Securities [Member]
Available-for-sale securities, amortized cost	312,869	345,981
Available-for-sale securities, gross unrealized gains	977	2,792
Available-for-sale securities, gross unrealized losses	(24,086)	(19,865)
Available-for-sale securities, fair market value	289,760	328,908
SBA Pool [Member]
Available-for-sale securities, amortized cost	989	1,394
Available-for-sale securities, gross unrealized gains	2	3
Available-for-sale securities, gross unrealized losses	(2)	(2)
Available-for-sale securities, fair market value	989	1,395
Corporate Debt Securities [Member]
Available-for-sale securities, amortized cost	43,500	47,500
Available-for-sale securities, gross unrealized gains	12	9
Available-for-sale securities, gross unrealized losses	(3,445)	(3,992)
Available-for-sale securities, fair market value	40,067	43,517
Asset-Backed Securities [Member]
Available-for-sale securities, amortized cost	43,921	56,613
Available-for-sale securities, gross unrealized gains	73	133
Available-for-sale securities, gross unrealized losses	(749)	(1,411)
Available-for-sale securities, fair market value	$ 43,245	$ 55,335

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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