Note 2 - Investment Securities - Held to Maturity Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Securities held-to-maturity, carrying value	$ 380,726	$ 439,837
Securities held-to-maturity, gains	0	1
Securities held-to-maturity, losses	(32,840)	(31,319)
Debt Securities, Held-to-Maturity, Fair Value	347,886	408,519
US Treasury Securities and US Government Agencies Debt Securities [Member]
Securities held-to-maturity, carrying value	153,536	203,259
Securities held-to-maturity, gains	0	0
Securities held-to-maturity, losses	(3,353)	(4,932)
Debt Securities, Held-to-Maturity, Fair Value	150,183	198,327
US Government-sponsored Enterprises Debt Securities [Member]
Securities held-to-maturity, carrying value	26,711	26,918
Securities held-to-maturity, gains	0	0
Securities held-to-maturity, losses	(2,637)	(2,457)
Debt Securities, Held-to-Maturity, Fair Value	24,074	24,461
Mortgage-Backed Security, Issued by US Government-Sponsored Enterprise [Member]
Securities held-to-maturity, carrying value	200,479	209,660
Securities held-to-maturity, gains	0	1
Securities held-to-maturity, losses	(26,850)	(23,930)
Debt Securities, Held-to-Maturity, Fair Value	$ 173,629	$ 185,731

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

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