Securities - Schedule of Debt Securities Components (Details) - USD ($) $ in Thousands		Sep. 30, 2022	Dec. 31, 2021
Available-for-sale [Abstract]
Amortized Cost		$ 1,592,891	$ 2,655,594
Gross unrealized gains		356	113,681
Gross unrealized losses		168,685	4,950
Securities AFS, at estimated fair value (amortized cost of $1,592,891 and $2,655,594, respectively)		1,424,562	2,764,325
HELD TO MATURITY
Amortized cost		1,151,205	90,780
Gross unrealized gains		22	4,455
Gross unrealized losses		207,905	0
Estimated Fair Value		943,322	95,235
US Treasury Securities
Available-for-sale [Abstract]
Amortized Cost			58,084
Gross unrealized gains			843
Gross unrealized losses			50
Securities AFS, at estimated fair value (amortized cost of $1,592,891 and $2,655,594, respectively)			58,877
State and political subdivisions
Available-for-sale [Abstract]
Amortized Cost		1,186,010	1,962,257
Gross unrealized gains		26	93,893
Gross unrealized losses		147,704	4,214
Securities AFS, at estimated fair value (amortized cost of $1,592,891 and $2,655,594, respectively)		1,038,332	2,051,936
HELD TO MATURITY
Amortized cost		918,216	788
Gross unrealized gains		0	3
Gross unrealized losses		190,841	0
Estimated Fair Value		727,375	791
Corporate bonds and other
Available-for-sale [Abstract]
Amortized Cost		60,144	133,333
Gross unrealized gains		67	2,408
Gross unrealized losses		2,794	209
Securities AFS, at estimated fair value (amortized cost of $1,592,891 and $2,655,594, respectively)		57,417	135,532
HELD TO MATURITY
Amortized cost		95,458
Gross unrealized gains		0
Gross unrealized losses		6,077
Estimated Fair Value		89,381
Residential
Available-for-sale [Abstract]
Amortized Cost	[1]	337,189	411,727
Gross unrealized gains	[1]	263	14,895
Gross unrealized losses	[1]	17,084	272
Securities AFS, at estimated fair value (amortized cost of $1,592,891 and $2,655,594, respectively)	[1]	320,368	426,350
HELD TO MATURITY
Amortized cost	[1]	94,539	38,644
Gross unrealized gains	[1]	22	2,103
Gross unrealized losses	[1]	8,383	0
Estimated Fair Value	[1]	86,178	40,747
Commercial
Available-for-sale [Abstract]
Amortized Cost	[1]	9,548	90,193
Gross unrealized gains	[1]	0	1,642
Gross unrealized losses	[1]	1,103	205
Securities AFS, at estimated fair value (amortized cost of $1,592,891 and $2,655,594, respectively)	[1]	8,445	91,630
HELD TO MATURITY
Amortized cost	[1]	42,992	51,348
Gross unrealized gains	[1]	0	2,349
Gross unrealized losses	[1]	2,604	0
Estimated Fair Value	[1]	$ 40,388	$ 53,697

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