Securities - Amortized Cost and Estimated Fair Value of Securities - Securities Held-to-maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Securities held-to-maturity:
Total	$ 650,577	$ 715,004
Gross Unrecognized Gains	285	244
Gross Unrecognized (Losses)	(86,735)	(100,796)
Estimated Fair Value	564,127	614,452
Allowance for credit loss current period	(12)	(14)
Agency mortgage-backed securities
Securities held-to-maturity:
Total	618,374	677,381
Gross Unrecognized Gains	282	235
Gross Unrecognized (Losses)	(86,011)	(99,977)
Estimated Fair Value	532,645	577,639
Municipals - exempt from Federal tax
Securities held-to-maturity:
Total	32,203	37,623
Gross Unrecognized Gains	3	9
Gross Unrecognized (Losses)	(724)	(819)
Estimated Fair Value	31,482	36,813
Allowance for credit loss current period	$ (12)	$ (14)

Not applicable.

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

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Amount excluding accrued interest, before 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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