Securities, Securities in Continuous Unrealized Loss Position (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Securities [Abstract]
Percentage of total investment with unrealized losses	96.80%	97.30%
Available-for-sale, amortized cost [Abstract]
Less than 12 months	$ 18,667	$ 35,971
12 months or more	1,200,303	1,234,191
Total	1,218,970	1,270,162
Available-for-sale, gross unrealized losses [Abstract]
Less than 12 months	(256)	(1,544)
12 months or more	(142,363)	(136,221)
Total	(142,619)	(137,765)
Available-for-sale, fair value [Abstract]
Less than 12 months	18,411	34,427
12 months or more	1,057,940	1,097,970
Total	1,076,351	1,132,397
U.S. Treasury and Government Agencies [Member]
Available-for-sale, amortized cost [Abstract]
Less than 12 months	2,785	3,761
12 months or more	351,685	361,038
Total	354,470	364,799
Available-for-sale, gross unrealized losses [Abstract]
Less than 12 months	(1)	(5)
12 months or more	(27,574)	(26,567)
Total	(27,575)	(26,572)
Available-for-sale, fair value [Abstract]
Less than 12 months	2,784	3,756
12 months or more	324,111	334,471
Total	326,895	338,227
State and Political Subdivisions [Member]
Available-for-sale, amortized cost [Abstract]
Less than 12 months	11,081	16,154
12 months or more	297,619	284,397
Total	308,700	300,551
Available-for-sale, gross unrealized losses [Abstract]
Less than 12 months	(234)	(1,250)
12 months or more	(49,574)	(47,040)
Total	(49,808)	(48,290)
Available-for-sale, fair value [Abstract]
Less than 12 months	10,847	14,904
12 months or more	248,045	237,357
Total	258,892	252,261
U.S. Government Sponsored Agency Mortgage-backed Securities [Member]
Available-for-sale, amortized cost [Abstract]
Less than 12 months	2,869	16,056
12 months or more	479,271	500,763
Total	482,140	516,819
Available-for-sale, gross unrealized losses [Abstract]
Less than 12 months	(18)	(289)
12 months or more	(64,756)	(61,847)
Total	(64,774)	(62,136)
Available-for-sale, fair value [Abstract]
Less than 12 months	2,851	15,767
12 months or more	414,515	438,916
Total	417,366	454,683
Asset-backed Securities [Member]
Available-for-sale, amortized cost [Abstract]
Less than 12 months	1,932	0
12 months or more	71,728	87,993
Total	73,660	87,993
Available-for-sale, gross unrealized losses [Abstract]
Less than 12 months	(3)	0
12 months or more	(459)	(767)
Total	(462)	(767)
Available-for-sale, fair value [Abstract]
Less than 12 months	1,929	0
12 months or more	71,269	87,226
Total	$ 73,198	$ 87,226