v3.26.3
Loans and the Allowance for Credit Losses - Summary of Aging Analysis of Portfolio Loans Restructured (Detail) - USD ($)
$ in Thousands
Sep. 30, 2026
Dec. 31, 2025
Sep. 30, 2025
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan $ 19,900,551 $ 19,226,432  
Loan Modification [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 125,230   $ 165,192
Home Equity [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 1,240,811 1,129,394  
Home Equity [Member] | Loan Modification [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 608   1,851
Commercial and Industrial [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 3,067,867 2,863,893  
Commercial and Industrial [Member] | Loan Modification [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 28,933   11,891
Commercial Real Estate [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 11,319,515 10,938,834  
Commercial Real Estate [Member] | Commercial Real Estate - Land and Construction [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 1,637,322 1,783,637  
Commercial Real Estate [Member] | Commercial Real Estate - Land and Construction [Member] | Loan Modification [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan     54,725
Commercial Real Estate [Member] | Commercial Real Estate - Improved Property [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 9,682,193 9,155,197  
Commercial Real Estate [Member] | Commercial Real Estate - Improved Property [Member] | Loan Modification [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 92,791   90,090
Residential Real Estate [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 3,998,944 3,938,585  
Residential Real Estate [Member] | Loan Modification [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 2,676   5,829
Consumer [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 273,414 355,726  
Consumer [Member] | Loan Modification [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 222   806
30-59 Days Past Due [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 74,244 45,847  
30-59 Days Past Due [Member] | Loan Modification [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan     304
30-59 Days Past Due [Member] | Home Equity [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 11,324 9,938  
30-59 Days Past Due [Member] | Home Equity [Member] | Loan Modification [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan     290
30-59 Days Past Due [Member] | Commercial and Industrial [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 7,325 2,055  
30-59 Days Past Due [Member] | Commercial Real Estate [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 51,995 26,997  
30-59 Days Past Due [Member] | Commercial Real Estate [Member] | Commercial Real Estate - Land and Construction [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 23,125 13,535  
30-59 Days Past Due [Member] | Commercial Real Estate [Member] | Commercial Real Estate - Improved Property [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 28,870 13,462  
30-59 Days Past Due [Member] | Residential Real Estate [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 397 738  
30-59 Days Past Due [Member] | Consumer [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 3,203 6,119  
30-59 Days Past Due [Member] | Consumer [Member] | Loan Modification [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan     14
60-89 Days Past Due [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 26,011 48,523  
60-89 Days Past Due [Member] | Loan Modification [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 96   2,072
60-89 Days Past Due [Member] | Home Equity [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 2,677 4,162  
60-89 Days Past Due [Member] | Home Equity [Member] | Loan Modification [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan     225
60-89 Days Past Due [Member] | Commercial and Industrial [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 3,282 7,434  
60-89 Days Past Due [Member] | Commercial Real Estate [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 3,805 21,592  
60-89 Days Past Due [Member] | Commercial Real Estate [Member] | Commercial Real Estate - Land and Construction [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 300 13,956  
60-89 Days Past Due [Member] | Commercial Real Estate [Member] | Commercial Real Estate - Land and Construction [Member] | Loan Modification [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan     293
60-89 Days Past Due [Member] | Commercial Real Estate [Member] | Commercial Real Estate - Improved Property [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 3,505 7,636  
60-89 Days Past Due [Member] | Residential Real Estate [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 14,889 13,513  
60-89 Days Past Due [Member] | Residential Real Estate [Member] | Loan Modification [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 96   1,513
60-89 Days Past Due [Member] | Consumer [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 1,358 1,822  
60-89 Days Past Due [Member] | Consumer [Member] | Loan Modification [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan     41
90 Days or More Past Due [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 120,596 106,268  
90 Days or More Past Due [Member] | Loan Modification [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 787   15,804
90 Days or More Past Due [Member] | Home Equity [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 7,469 8,642  
90 Days or More Past Due [Member] | Home Equity [Member] | Loan Modification [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 250   425
90 Days or More Past Due [Member] | Commercial and Industrial [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 12,539 16,157  
90 Days or More Past Due [Member] | Commercial and Industrial [Member] | Loan Modification [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 75   7,894
90 Days or More Past Due [Member] | Commercial Real Estate [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 62,367 44,771  
90 Days or More Past Due [Member] | Commercial Real Estate [Member] | Commercial Real Estate - Land and Construction [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 27,313 832  
90 Days or More Past Due [Member] | Commercial Real Estate [Member] | Commercial Real Estate - Land and Construction [Member] | Loan Modification [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan     832
90 Days or More Past Due [Member] | Commercial Real Estate [Member] | Commercial Real Estate - Improved Property [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 35,054 43,939  
90 Days or More Past Due [Member] | Commercial Real Estate [Member] | Commercial Real Estate - Improved Property [Member] | Loan Modification [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan     5,312
90 Days or More Past Due [Member] | Residential Real Estate [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 37,582 34,840  
90 Days or More Past Due [Member] | Residential Real Estate [Member] | Loan Modification [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 462   1,247
90 Days or More Past Due [Member] | Consumer [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 639 1,858  
90 Days or More Past Due [Member] | Consumer [Member] | Loan Modification [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan     94
Total Past Due [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 220,851 200,638  
Total Past Due [Member] | Loan Modification [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 883   18,180
Total Past Due [Member] | Home Equity [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 21,470 22,742  
Total Past Due [Member] | Home Equity [Member] | Loan Modification [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 250   940
Total Past Due [Member] | Commercial and Industrial [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 23,146 25,646  
Total Past Due [Member] | Commercial and Industrial [Member] | Loan Modification [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 75   7,894
Total Past Due [Member] | Commercial Real Estate [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 118,167 93,360  
Total Past Due [Member] | Commercial Real Estate [Member] | Commercial Real Estate - Land and Construction [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 50,738 28,323  
Total Past Due [Member] | Commercial Real Estate [Member] | Commercial Real Estate - Land and Construction [Member] | Loan Modification [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan     1,125
Total Past Due [Member] | Commercial Real Estate [Member] | Commercial Real Estate - Improved Property [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 67,429 65,037  
Total Past Due [Member] | Commercial Real Estate [Member] | Commercial Real Estate - Improved Property [Member] | Loan Modification [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan     5,312
Total Past Due [Member] | Residential Real Estate [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 52,868 49,091  
Total Past Due [Member] | Residential Real Estate [Member] | Loan Modification [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 558   2,760
Total Past Due [Member] | Consumer [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 5,200 9,799  
Total Past Due [Member] | Consumer [Member] | Loan Modification [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 0   149
Current [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 19,679,700 19,025,794  
Current [Member] | Loan Modification [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 124,347   147,012
Current [Member] | Home Equity [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 1,219,341 1,106,652  
Current [Member] | Home Equity [Member] | Loan Modification [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 358   911
Current [Member] | Commercial and Industrial [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 3,044,721 2,838,247  
Current [Member] | Commercial and Industrial [Member] | Loan Modification [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 28,858   3,997
Current [Member] | Commercial Real Estate [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 11,201,348 10,845,474  
Current [Member] | Commercial Real Estate [Member] | Commercial Real Estate - Land and Construction [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 1,586,584 1,755,314  
Current [Member] | Commercial Real Estate [Member] | Commercial Real Estate - Land and Construction [Member] | Loan Modification [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan     53,600
Current [Member] | Commercial Real Estate [Member] | Commercial Real Estate - Improved Property [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 9,614,764 9,090,160  
Current [Member] | Commercial Real Estate [Member] | Commercial Real Estate - Improved Property [Member] | Loan Modification [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 92,791   84,778
Current [Member] | Residential Real Estate [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 3,946,076 3,889,494  
Current [Member] | Residential Real Estate [Member] | Loan Modification [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 2,118   3,069
Current [Member] | Consumer [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan 268,214 $ 345,927  
Current [Member] | Consumer [Member] | Loan Modification [Member]      
Financing Receivable, Modified, Past Due [Line Items]      
Total modified loan $ 222   $ 657