Note 2 - Investment Securities - Held to Maturity Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Securities held-to-maturity, carrying value	$ 374,912	$ 439,837
Securities held-to-maturity, gains	3	1
Securities held-to-maturity, losses	(22,485)	(31,319)
Debt Securities, Held-to-Maturity, Fair Value	352,430	408,519
US Treasury Securities and US Government Agencies Debt Securities [Member]
Securities held-to-maturity, carrying value	153,692	203,259
Securities held-to-maturity, gains	0	0
Securities held-to-maturity, losses	(1,539)	(4,932)
Debt Securities, Held-to-Maturity, Fair Value	152,153	198,327
US Government-sponsored Enterprises Debt Securities [Member]
Securities held-to-maturity, carrying value	25,726	26,918
Securities held-to-maturity, gains	0	0
Securities held-to-maturity, losses	(1,478)	(2,457)
Debt Securities, Held-to-Maturity, Fair Value	24,248	24,461
Mortgage-Backed Security, Issued by US Government-Sponsored Enterprise [Member]
Securities held-to-maturity, carrying value	195,494	209,660
Securities held-to-maturity, gains	3	1
Securities held-to-maturity, losses	(19,468)	(23,930)
Debt Securities, Held-to-Maturity, Fair Value	$ 176,029	$ 185,731

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

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