Securities - Schedule of Debt Securities Components (Details) - USD ($) $ in Thousands		Jun. 30, 2023	Dec. 31, 2022
Available-for-sale [Abstract]
Amortized Cost		$ 1,409,568	$ 1,387,874
Gross unrealized gains		1,077	1,282
Gross unrealized losses		70,824	90,142
Securities AFS, at estimated fair value (amortized cost of $1,409,568 and $1,387,874, respectively)		1,339,821	1,299,014
HELD TO MATURITY
Amortized cost		1,308,472	1,326,729
Gross unrealized gains		7,523	4,565
Gross unrealized losses		167,180	182,138
Estimated Fair Value		1,148,815	1,149,156
US Treasury Securities
Available-for-sale [Abstract]
Amortized Cost		298,907
Gross unrealized gains		91
Gross unrealized losses		0
Securities AFS, at estimated fair value (amortized cost of $1,409,568 and $1,387,874, respectively)		298,998
State and political subdivisions
Available-for-sale [Abstract]
Amortized Cost		826,193	1,039,453
Gross unrealized gains		750	956
Gross unrealized losses		56,660	75,557
Securities AFS, at estimated fair value (amortized cost of $1,409,568 and $1,387,874, respectively)		770,283	964,852
HELD TO MATURITY
Amortized cost		1,038,551	1,037,556
Gross unrealized gains		7,093	3,969
Gross unrealized losses		139,616	163,283
Estimated Fair Value		906,028	878,242
Corporate bonds and other
Available-for-sale [Abstract]
Amortized Cost		14,532	8,692
Gross unrealized gains		18	26
Gross unrealized losses		1,559	14
Securities AFS, at estimated fair value (amortized cost of $1,409,568 and $1,387,874, respectively)		12,991	8,704
HELD TO MATURITY
Amortized cost		146,371	152,552
Gross unrealized gains		421	575
Gross unrealized losses		16,895	7,993
Estimated Fair Value		129,897	145,134
Residential
Available-for-sale [Abstract]
Amortized Cost	[1]	258,683	328,400
Gross unrealized gains	[1]	171	250
Gross unrealized losses	[1]	11,621	13,623
Securities AFS, at estimated fair value (amortized cost of $1,409,568 and $1,387,874, respectively)	[1]	247,233	315,027
HELD TO MATURITY
Amortized cost	[1]	92,920	93,796
Gross unrealized gains	[1]	9	21
Gross unrealized losses	[1]	8,225	8,343
Estimated Fair Value	[1]	84,704	85,474
Commercial
Available-for-sale [Abstract]
Amortized Cost	[1]	11,253	11,329
Gross unrealized gains	[1]	47	50
Gross unrealized losses	[1]	984	948
Securities AFS, at estimated fair value (amortized cost of $1,409,568 and $1,387,874, respectively)	[1]	10,316	10,431
HELD TO MATURITY
Amortized cost	[1]	30,630	42,825
Gross unrealized gains	[1]	0	0
Gross unrealized losses	[1]	2,444	2,519
Estimated Fair Value	[1]	$ 28,186	$ 40,306

[1] All MBS are issued and/or guaranteed by U.S. government agencies or U.S. GSEs.