v3.26.1
Loans and Allowance for Credit Losses - Outstanding Balances of Loan (Detail) - USD ($)
$ in Thousands
 3 Months Ended
Mar. 31, 2026
Dec. 31, 2025
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss $ 9,433,825 $ 9,508,039
Default Status Of TDRs After Number Of Days Past Due 90 days  
Time and Demand Loans    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss $ 1,196,447 1,226,054
Commercial Credit Cards    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 11,919 11,408
Senior Lien    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 1,613,180 1,631,019
Junior Lien    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 738,421 729,266
Multifamily    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 606,179 594,790
Nonowner Occupied Commercial Real Estate    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 1,776,985 1,834,016
Owner Occupied Commercial Real Estate    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 765,603 753,303
Automobiles    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 1,367,360 1,387,195
Consumer Credit Cards    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 8,886 9,496
Other Consumer Loans    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 59,080 61,179
Equipment Finance    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 746,723 693,265
Time and Demand Loans Other    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 106,805 114,262
Construction Other    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 404,394 415,536
Construction Residential    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 31,843 47,250
Commercial, financial, agricultural and other [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 2,061,894 2,044,989
Commercial, financial, agricultural and other [Member] | Time and Demand Loans    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 1,196,447 1,226,054
Commercial, financial, agricultural and other [Member] | Commercial Credit Cards    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 11,919 11,408
Commercial, financial, agricultural and other [Member] | Equipment Finance    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 746,723 693,265
Commercial, financial, agricultural and other [Member] | Time and Demand Loans Other    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 106,805 114,262
Real estate construction [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 436,237 462,786
Real estate construction [Member] | Construction Other    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 404,394 415,536
Real estate construction [Member] | Construction Residential    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 31,843 47,250
Residential real estate [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 2,351,601 2,360,285
Residential real estate [Member] | Senior Lien    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 1,613,180 1,631,019
Residential real estate [Member] | Junior Lien    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 738,421 729,266
Commercial Real Estate [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 3,148,767 3,182,109
Commercial Real Estate [Member] | Multifamily    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 606,179 594,790
Commercial Real Estate [Member] | Nonowner Occupied Commercial Real Estate    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 1,776,985 1,834,016
Commercial Real Estate [Member] | Owner Occupied Commercial Real Estate    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 765,603 753,303
Loans to individuals [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 1,435,326 1,457,870
Loans to individuals [Member] | Automobiles    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 1,367,360 1,387,195
Loans to individuals [Member] | Consumer Credit Cards    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 8,886 9,496
Loans to individuals [Member] | Other Consumer Loans    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss $ 59,080 $ 61,179