Investment Securities - Amortized Cost and Estimated Fair Value - Held-to-Maturity Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Debt Securities, Held-to-Maturity, Fair Value to Amortized Cost, after Allowance for Credit Loss [Abstract]
Amortized Cost	$ 320,073	$ 336,944
Gross Unrecognized Gains	5,909	585
Gross Unrecognized Losses	(11,058)	(9,518)
Securities held-to-maturity	314,924	328,011
Allowance for credit losses on held-to-maturity securities	(16)	(63)
U.S. Government Agencies [Member]
Debt Securities, Held-to-Maturity, Fair Value to Amortized Cost, after Allowance for Credit Loss [Abstract]
Amortized Cost	5,522	6,047
Gross Unrecognized Losses	(617)	(621)
Securities held-to-maturity	4,905	5,426
Mortgage-Backed Securities [Member]
Debt Securities, Held-to-Maturity, Fair Value to Amortized Cost, after Allowance for Credit Loss [Abstract]
Amortized Cost	142,295	157,473
Gross Unrecognized Losses	(10,441)	(9,915)
Securities held-to-maturity	131,854	147,558
States and Political Subdivisions [Member]
Debt Securities, Held-to-Maturity, Fair Value to Amortized Cost, after Allowance for Credit Loss [Abstract]
Amortized Cost	172,256	173,424
Gross Unrecognized Gains	5,909	585
Gross Unrecognized Losses		(1,018)
Securities held-to-maturity	178,165	175,027
Allowance for credit losses on held-to-maturity securities	$ (16)	$ (63)