Investment Securities - Available-for-sale Securities (Details) - USD ($) $ in Thousands		Sep. 30, 2023	Dec. 31, 2022
Schedule of Available-for-sale Securities
Amortized Cost		$ 1,211,794	$ 1,300,719
Gross Unrealized Gains		732	1,104
Gross Unrealized Losses		(193,945)	(170,424)
Fair Value	[1]	1,018,581	1,131,399
U.S. Treasury and government agencies
Schedule of Available-for-sale Securities
Amortized Cost		45,207	158,473
Gross Unrealized Gains		0	0
Gross Unrealized Losses		(2,741)	(6,051)
Fair Value		42,466	152,422
U.S. government sponsored agencies
Schedule of Available-for-sale Securities
Amortized Cost		118,148	101,753
Gross Unrealized Gains		0	18
Gross Unrealized Losses		(14,216)	(13,656)
Fair Value		103,932	88,115
States and political subdivisions
Schedule of Available-for-sale Securities
Amortized Cost		263,001	261,612
Gross Unrealized Gains		6	12
Gross Unrealized Losses		(42,547)	(35,742)
Fair Value		220,460	225,882
Residential mortgage-backed securities
Schedule of Available-for-sale Securities
Amortized Cost		714,501	707,025
Gross Unrealized Gains		725	1,017
Gross Unrealized Losses		(122,122)	(103,389)
Fair Value		593,104	604,653
Commercial mortgage-backed securities
Schedule of Available-for-sale Securities
Amortized Cost		62,584	61,091
Gross Unrealized Gains		0	0
Gross Unrealized Losses		(11,744)	(11,042)
Fair Value		50,840	50,049
Bank-issued trust preferred securities
Schedule of Available-for-sale Securities
Amortized Cost		8,353	10,765
Gross Unrealized Gains		1	57
Gross Unrealized Losses		(575)	(544)
Fair Value		$ 7,779	$ 10,278

[1]     Available-for-sale investment securities and held-to-maturity investment securities are presented net of allowance for credit losses of $0 and $238, respectively, at September 30, 2023, and $0 and $241, respectively, at December 31, 2022.