Note 4 - Investment Securities - Held to Maturity Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Securities held-to-maturity, carrying value	$ 473,217	$ 0
Securities held-to-maturity, gains	0
Securities held-to-maturity, losses	(41,384)
Debt Securities, Held-to-Maturity, Fair Value, Total	431,833	$ 0
US Treasury Securities and US Government Agencies Debt Securities [Member]
Securities held-to-maturity, carrying value	217,794
Securities held-to-maturity, gains	0
Securities held-to-maturity, losses	(9,166)
Debt Securities, Held-to-Maturity, Fair Value, Total	208,628
US Government-sponsored Enterprises Debt Securities [Member]
Securities held-to-maturity, carrying value	27,507
Securities held-to-maturity, gains	0
Securities held-to-maturity, losses	(2,559)
Debt Securities, Held-to-Maturity, Fair Value, Total	24,948
Mortgage-Backed Securities, Issued by US Government Sponsored Enterprises [Member]
Securities held-to-maturity, carrying value	227,916
Securities held-to-maturity, gains	0
Securities held-to-maturity, losses	(29,659)
Debt Securities, Held-to-Maturity, Fair Value, Total	$ 198,257

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

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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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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Fair value of investment in debt security measured at amortized cost (held-to-maturity).

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