Securities, Securities in Continuous Unrealized Loss Position (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Securities [Abstract]
Percentage of total investment with unrealized losses	98.00%	97.40%
Available-for-sale, amortized cost [Abstract]
Less than 12 months	$ 106,931	$ 416,778
12 months or more	1,258,638	981,280
Total	1,365,569	1,398,058
Available-for-sale, gross unrealized losses [Abstract]
Less than 12 months	(3,146)	(21,324)
12 months or more	(146,742)	(153,300)
Total	(149,888)	(174,624)
Available-for-sale, fair value [Abstract]
Less than 12 months	103,785	395,454
12 months or more	1,111,896	827,980
Total	1,215,681	1,223,434
U.S. Treasury and Government Agencies [Member]
Available-for-sale, amortized cost [Abstract]
Less than 12 months	5,825	144,305
12 months or more	389,733	249,424
Total	395,558	393,729
Available-for-sale, gross unrealized losses [Abstract]
Less than 12 months	(4)	(6,953)
12 months or more	(30,628)	(29,906)
Total	(30,632)	(36,859)
Available-for-sale, fair value [Abstract]
Less than 12 months	5,821	137,352
12 months or more	359,105	219,518
Total	364,926	356,870
State and Political Subdivisions [Member]
Available-for-sale, amortized cost [Abstract]
Less than 12 months	28,387	94,277
12 months or more	275,555	225,019
Total	303,942	319,296
Available-for-sale, gross unrealized losses [Abstract]
Less than 12 months	(1,148)	(6,257)
12 months or more	(49,639)	(55,419)
Total	(50,787)	(61,676)
Available-for-sale, fair value [Abstract]
Less than 12 months	27,239	88,020
12 months or more	225,916	169,600
Total	253,155	257,620
U.S. Government Sponsored Agency Mortgage-backed Securities [Member]
Available-for-sale, amortized cost [Abstract]
Less than 12 months	65,273	139,314
12 months or more	510,356	454,357
Total	575,629	593,671
Available-for-sale, gross unrealized losses [Abstract]
Less than 12 months	(1,837)	(6,883)
12 months or more	(64,803)	(66,950)
Total	(66,640)	(73,833)
Available-for-sale, fair value [Abstract]
Less than 12 months	63,436	132,431
12 months or more	445,553	387,407
Total	508,989	519,838
Asset-backed Securities [Member]
Available-for-sale, amortized cost [Abstract]
Less than 12 months	7,446	38,882
12 months or more	82,994	52,480
Total	90,440	91,362
Available-for-sale, gross unrealized losses [Abstract]
Less than 12 months	(157)	(1,231)
12 months or more	(1,672)	(1,025)
Total	(1,829)	(2,256)
Available-for-sale, fair value [Abstract]
Less than 12 months	7,289	37,651
12 months or more	81,322	51,455
Total	$ 88,611	$ 89,106