v3.26.3
Loans and the Allowance for Credit Losses - Summary of Age Analysis by Loan Category (Detail) - USD ($)
$ in Thousands
Sep. 30, 2026
Dec. 31, 2025
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income $ 19,900,551 $ 19,226,432
90 Days or More Past Due and Accruing 23,719 37,783
Loans held for sale 56,707 87,454
Total loans, current 19,717,245 19,113,248
Total loans 19,957,258 19,313,886
Home Equity [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 1,240,811 1,129,394
90 Days or More Past Due and Accruing 2,020 2,882
Commercial Real Estate [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 11,319,515 10,938,834
90 Days or More Past Due and Accruing 9,178 20,507
Residential Real Estate [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 3,998,944 3,938,585
90 Days or More Past Due and Accruing 11,332 12,479
Consumer [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 273,414 355,726
90 Days or More Past Due and Accruing 792 1,138
Commercial Real Estate - Land and Construction [Member] | Commercial Real Estate [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 1,637,322 1,783,637
Commercial Real Estate - Improved Property [Member] | Commercial Real Estate [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 9,682,193 9,155,197
90 Days or More Past Due and Accruing 9,178 20,507
Commercial and Industrial [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 3,067,867 2,863,893
90 Days or More Past Due and Accruing 397 777
Non-accrual Loans [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 174,132 91,584
Current [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 19,679,700 19,025,794
Loans held for sale, current 37,545 87,454
Current [Member] | Home Equity [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 1,219,341 1,106,652
Current [Member] | Commercial Real Estate [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 11,201,348 10,845,474
Current [Member] | Residential Real Estate [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 3,946,076 3,889,494
Current [Member] | Consumer [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 268,214 345,927
Current [Member] | Commercial Real Estate - Land and Construction [Member] | Commercial Real Estate [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 1,586,584 1,755,314
Current [Member] | Commercial Real Estate - Improved Property [Member] | Commercial Real Estate [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 9,614,764 9,090,160
Current [Member] | Commercial and Industrial [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 3,044,721 2,838,247
Current [Member] | Non-accrual Loans [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 46,428 19,928
30-59 Days Past Due [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 74,244 45,847
30-59 Days Past Due [Member] | Home Equity [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 11,324 9,938
30-59 Days Past Due [Member] | Commercial Real Estate [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 51,995 26,997
30-59 Days Past Due [Member] | Residential Real Estate [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 397 738
30-59 Days Past Due [Member] | Consumer [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 3,203 6,119
30-59 Days Past Due [Member] | Commercial Real Estate - Land and Construction [Member] | Commercial Real Estate [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 23,125 13,535
30-59 Days Past Due [Member] | Commercial Real Estate - Improved Property [Member] | Commercial Real Estate [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 28,870 13,462
30-59 Days Past Due [Member] | Commercial and Industrial [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 7,325 2,055
30-59 Days Past Due [Member] | Non-accrual Loans [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 6,339 1,215
60-89 Days Past Due [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 26,011 48,523
60-89 Days Past Due [Member] | Home Equity [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 2,677 4,162
60-89 Days Past Due [Member] | Commercial Real Estate [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 3,805 21,592
60-89 Days Past Due [Member] | Residential Real Estate [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 14,889 13,513
60-89 Days Past Due [Member] | Consumer [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 1,358 1,822
60-89 Days Past Due [Member] | Commercial Real Estate - Land and Construction [Member] | Commercial Real Estate [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 300 13,956
60-89 Days Past Due [Member] | Commercial Real Estate - Improved Property [Member] | Commercial Real Estate [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 3,505 7,636
60-89 Days Past Due [Member] | Commercial and Industrial [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 3,282 7,434
60-89 Days Past Due [Member] | Non-accrual Loans [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 5,326 1,956
90 Days or More Past Due [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 120,596 106,268
Loans held for sale 19,162  
Total loans 139,758  
90 Days or More Past Due [Member] | Home Equity [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 7,469 8,642
90 Days or More Past Due [Member] | Commercial Real Estate [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 62,367 44,771
90 Days or More Past Due [Member] | Residential Real Estate [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 37,582 34,840
90 Days or More Past Due [Member] | Consumer [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 639 1,858
90 Days or More Past Due [Member] | Commercial Real Estate - Land and Construction [Member] | Commercial Real Estate [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 27,313 832
90 Days or More Past Due [Member] | Commercial Real Estate - Improved Property [Member] | Commercial Real Estate [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 35,054 43,939
90 Days or More Past Due [Member] | Commercial and Industrial [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 12,539 16,157
90 Days or More Past Due [Member] | Non-accrual Loans [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 116,039 68,485
Total Past Due [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 220,851 200,638
Loans held for sale 19,162  
Total loans 240,013  
Total Past Due [Member] | Home Equity [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 21,470 22,742
Total Past Due [Member] | Commercial Real Estate [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 118,167 93,360
Total Past Due [Member] | Residential Real Estate [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 52,868 49,091
Total Past Due [Member] | Consumer [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 5,200 9,799
Total Past Due [Member] | Commercial Real Estate - Land and Construction [Member] | Commercial Real Estate [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 50,738 28,323
Total Past Due [Member] | Commercial Real Estate - Improved Property [Member] | Commercial Real Estate [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 67,429 65,037
Total Past Due [Member] | Commercial and Industrial [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income 23,146 25,646
Total Past Due [Member] | Non-accrual Loans [Member]    
Financing Receivable, Recorded Investment [Line Items]    
Portfolio loans, net of unearned income $ 127,704 $ 71,656