Investment Securities - Held to Maturity Continuous Loss Position (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Fair Value
Less Than 12 Months	$ 18,041	$ 23,438
12 Months or Greater	367,024	386,766
Total	385,065	410,204
Gross Unrealized Losses
Less Than 12 Months	(1,349)	(2,121)
12 Months or Greater	(64,642)	(52,505)
Total	(65,991)	(54,626)
U.S. treasury securities
Fair Value
Less Than 12 Months	0	0
12 Months or Greater	87,397	87,466
Total	87,397	87,466
Gross Unrealized Losses
Less Than 12 Months	0	0
12 Months or Greater	(5,483)	(4,149)
Total	(5,483)	(4,149)
U.S. agency securities
Fair Value
Less Than 12 Months	0	0
12 Months or Greater	14,339	14,571
Total	14,339	14,571
Gross Unrealized Losses
Less Than 12 Months	0	0
12 Months or Greater	(1,975)	(1,838)
Total	(1,975)	(1,838)
State, county & municipal securities
Fair Value
Less Than 12 Months	18,041	9,858
12 Months or Greater	95,519	105,734
Total	113,560	115,592
Gross Unrealized Losses
Less Than 12 Months	(1,349)	(1,392)
12 Months or Greater	(21,637)	(18,126)
Total	(22,986)	(19,518)
Mortgage-backed securities
Fair Value
Less Than 12 Months	0	13,580
12 Months or Greater	169,769	178,995
Total	169,769	192,575
Gross Unrealized Losses
Less Than 12 Months	0	(729)
12 Months or Greater	(35,547)	(28,392)
Total	$ (35,547)	$ (29,121)