v3.26.1
Loans and Allowance for Credit Losses - Outstanding Balances of Loan (Detail) - USD ($)
$ in Thousands
 6 Months Ended
Jun. 30, 2026
Dec. 31, 2025
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss $ 9,467,229 $ 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 $ 1,151,708 1,226,054
Commercial Credit Cards    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 12,135 11,408
Senior Lien    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 1,605,497 1,631,019
Junior Lien    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 762,669 729,266
Multifamily    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 636,826 594,790
Nonowner Occupied Commercial Real Estate    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 1,690,230 1,834,016
Owner Occupied Commercial Real Estate    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 756,718 753,303
Automobiles    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 1,390,894 1,387,195
Consumer Credit Cards    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 8,819 9,496
Other Consumer Loans    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 57,523 61,179
Equipment Finance    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 784,754 693,265
Time and Demand Loans Other    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 122,790 114,262
Construction Other    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 456,253 415,536
Construction Residential    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 30,413 47,250
Commercial, financial, agricultural and other [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 2,071,387 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 1,151,708 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 12,135 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 784,754 693,265
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 122,790 114,262
Real estate construction [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 486,666 462,786
Real estate construction [Member] | Construction Other    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 456,253 415,536
Real estate construction [Member] | Construction Residential    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 30,413 47,250
Residential real estate [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 2,368,166 2,360,285
Residential real estate [Member] | Senior Lien    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 1,605,497 1,631,019
Residential real estate [Member] | Junior Lien    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 762,669 729,266
Commercial Real Estate [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 3,083,774 3,182,109
Commercial Real Estate [Member] | Multifamily    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 636,826 594,790
Commercial Real Estate [Member] | Nonowner Occupied Commercial Real Estate    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 1,690,230 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 756,718 753,303
Loans to individuals [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 1,457,236 1,457,870
Loans to individuals [Member] | Automobiles    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss 1,390,894 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 8,819 9,496
Loans to individuals [Member] | Other Consumer Loans    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, before Allowance for Credit Loss $ 57,523 $ 61,179