Loans and Allowance for Credit Losses - Schedule of Age Analysis of Past Due Loans (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance	$ 11,444,216	$ 11,650,350
90 days past due and still accruing	1,343	3,479
Nonaccrual	44,663	35,994
Current or less than 30 days past due
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance	11,363,135	11,550,951
30 - 89 days past due
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance	35,075	59,926
Total commercial loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance	7,062,565	7,198,302
90 days past due and still accruing	34	256
Nonaccrual	17,211	14,234
Total commercial loans | Current or less than 30 days past due
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance	7,035,370	7,158,668
Total commercial loans | 30 - 89 days past due
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance	9,950	25,144
Construction and development
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance	570,749	552,676
90 days past due and still accruing	0	0
Nonaccrual	81	244
Construction and development | Current or less than 30 days past due
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance	570,668	552,127
Construction and development | 30 - 89 days past due
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance	0	305
Commercial, financial & agricultural
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance	1,761,287	1,874,906
90 days past due and still accruing	34	256
Nonaccrual	5,581	2,961
Commercial, financial & agricultural | Current or less than 30 days past due
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance	1,751,575	1,856,053
Commercial, financial & agricultural | 30 - 89 days past due
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance	4,097	15,636
Commercial real estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance	4,730,529	4,770,720
90 days past due and still accruing	0	0
Nonaccrual	11,549	11,029
Commercial real estate | Current or less than 30 days past due
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance	4,713,127	4,750,488
Commercial real estate | 30 - 89 days past due
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance	5,853	9,203
Commercial real estate | Non-owner-occupied commercial real estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance	3,150,269	3,197,765
90 days past due and still accruing	0	0
Nonaccrual	9,007	6,889
Commercial real estate | Non-owner-occupied commercial real estate | Current or less than 30 days past due
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance	3,137,206	3,183,234
Commercial real estate | Non-owner-occupied commercial real estate | 30 - 89 days past due
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance	4,056	7,642
Commercial real estate | Owner-occupied commercial real estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance	1,580,260	1,572,955
90 days past due and still accruing	0	0
Nonaccrual	2,542	4,140
Commercial real estate | Owner-occupied commercial real estate | Current or less than 30 days past due
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance	1,575,921	1,567,254
Commercial real estate | Owner-occupied commercial real estate | 30 - 89 days past due
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance	1,797	1,561
Total residential and consumer loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance	4,381,651	4,452,048
90 days past due and still accruing	1,309	3,223
Nonaccrual	27,452	21,760
Total residential and consumer loans | Current or less than 30 days past due
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance	4,327,765	4,392,283
Total residential and consumer loans | 30 - 89 days past due
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance	25,125	34,782
Residential real estate | Residential real estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance	3,321,101	3,105,760
90 days past due and still accruing	862	2,745
Nonaccrual	23,893	14,798
Residential real estate | Residential real estate | Current or less than 30 days past due
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance	3,283,403	3,070,437
Residential real estate | Residential real estate | 30 - 89 days past due
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance	12,943	17,780
Residential real estate | Home equity lines of credit
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance	410,845	349,011
90 days past due and still accruing	167	149
Nonaccrual	1,203	1,037
Residential real estate | Home equity lines of credit | Current or less than 30 days past due
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance	408,114	346,367
Residential real estate | Home equity lines of credit | 30 - 89 days past due
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance	1,361	1,458
Consumer | Home equity lines of credit
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance		349,011
Consumer | Consumer credit card
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance	98,310	93,825
90 days past due and still accruing	280	329
Nonaccrual	0	0
Consumer | Consumer credit card | Current or less than 30 days past due
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance	96,988	91,539
Consumer | Consumer credit card | 30 - 89 days past due
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance	1,042	1,957
Consumer | Other consumer loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance	551,395	903,452
90 days past due and still accruing	0
Nonaccrual	2,356
Consumer | Other consumer loans | Current or less than 30 days past due
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance	539,260	883,941
Consumer | Other consumer loans | 30 - 89 days past due
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance	$ 9,779	13,587
Consumer | Other consumer loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance		903,452
90 days past due and still accruing		0
Nonaccrual		5,925
Consumer | Other consumer loans | Current or less than 30 days past due
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance		883,940
Consumer | Other consumer loans | 30 - 89 days past due
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unpaid principal balance		$ 13,587