Note 6 - Investment Securities - Summary of Held-to-maturity Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Held to maturity, amortized cost	$ 402,237	$ 406,590
Held to maturity, gross unrealized gains	0	0
Held to maturity, gross unrealized losses	26,285	31,298
Held to maturity, fair value	375,952	375,292
US Government Agencies Debt Securities [Member]
Held to maturity, amortized cost	4,018	4,002
Held to maturity, gross unrealized gains	0	0
Held to maturity, gross unrealized losses	364	367
Held to maturity, fair value	3,654	3,635
Collateralized Mortgage-Backed Securities [Member]
Held to maturity, amortized cost	305,356	309,748
Held to maturity, gross unrealized gains	0	0
Held to maturity, gross unrealized losses	21,219	24,654
Held to maturity, fair value	284,137	285,094
State, County and Municipal [Member]
Held to maturity, amortized cost	92,863	92,840
Held to maturity, gross unrealized gains	0	0
Held to maturity, gross unrealized losses	4,702	6,277
Held to maturity, fair value	$ 88,161	$ 86,563

Amount, after allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity).

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Amount of accumulated unrecognized gain on investment in debt security measured at amortized cost (held-to-maturity).

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