v3.26.3
Fair Value Measurements - Schedule of Financial Assets and Liabilities Measured at Fair Value (Detail) - USD ($)
$ in Thousands
Sep. 30, 2026
Dec. 31, 2025
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale equity securities $ 25,765 $ 34,760
Loans held for sale 17,712 31,277
Derivative financial assets 1,174 789
Derivative financial liabilities 0 70
Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale debt securities 3,500,495 3,059,452
Available for sale equity securities 25,765 34,760
Loans held for sale 17,712 31,277
Derivative financial assets 1,174 789
Derivative financial liabilities 0 70
U.S. Treasury securities and obligations of U.S. Government corporations and agencies [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale debt securities 271,749 281,657
State and Political Subdivisions [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale debt securities 476,604 516,926
Residential Mortgage-Backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Agency [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale debt securities 2,089,347 1,358,636
Residential Mortgage-Backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Non-Agency [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale debt securities 27,829 38,885
Commercial Mortgage-Backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Agency [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale debt securities 300,853 395,073
Asset-Backed Securities [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale debt securities 149,596 223,254
Single issue trust preferred securities [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale debt securities 12,984 12,658
Other corporate securities [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale debt securities 171,533 232,363
Financial Services Industry [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale equity securities 14,634 25,825
Fixed Income Mutual Funds [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale equity securities 5,072 5,325
Interest Rate Swap Contracts [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative financial assets 543 316
Forward loan sales commitments [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative financial assets 13 15
Interest Rate Lock Commitments [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative financial assets 30 458
TBA Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative financial assets 588  
Derivative financial liabilities 0 70
Equity Mutual Funds [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale equity securities 6,059 3,610
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Loans held for sale 0 0
Derivative financial assets 0 0
Derivative financial liabilities 0 0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale debt securities 4,431 4,678
Available for sale equity securities 25,765 29,356
Loans held for sale 0 0
Derivative financial assets 0 0
Derivative financial liabilities 0 0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | U.S. Treasury securities and obligations of U.S. Government corporations and agencies [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale debt securities 0 0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | State and Political Subdivisions [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale debt securities 0 0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Residential Mortgage-Backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Agency [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale debt securities 0 0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Residential Mortgage-Backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Non-Agency [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale debt securities 0 0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Commercial Mortgage-Backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Agency [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale debt securities 0 0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Asset-Backed Securities [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale debt securities 0 0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Single issue trust preferred securities [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale debt securities 0 0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Other corporate securities [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale debt securities 4,431 4,678
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Financial Services Industry [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale equity securities 14,634 20,421
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fixed Income Mutual Funds [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale equity securities 5,072 5,325
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Interest Rate Swap Contracts [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative financial assets 0 0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Forward loan sales commitments [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative financial assets 0 0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Interest Rate Lock Commitments [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative financial assets 0 0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | TBA Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative financial assets 0  
Derivative financial liabilities 0 0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Equity Mutual Funds [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale equity securities 6,059 3,610
Significant Other Observable Inputs (Level 2) [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Loans held for sale 0 0
Derivative financial assets 543 316
Derivative financial liabilities 0 70
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale debt securities 3,496,064 3,054,774
Available for sale equity securities 0 5,404
Loans held for sale 0 0
Derivative financial assets 543 316
Derivative financial liabilities 0 0
Significant Other Observable Inputs (Level 2) [Member] | U.S. Treasury securities and obligations of U.S. Government corporations and agencies [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale debt securities 271,749 281,657
Significant Other Observable Inputs (Level 2) [Member] | State and Political Subdivisions [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale debt securities 476,604 516,926
Significant Other Observable Inputs (Level 2) [Member] | Residential Mortgage-Backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Agency [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale debt securities 2,089,347 1,358,636
Significant Other Observable Inputs (Level 2) [Member] | Residential Mortgage-Backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Non-Agency [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale debt securities 27,829 38,885
Significant Other Observable Inputs (Level 2) [Member] | Commercial Mortgage-Backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Agency [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale debt securities 300,853 395,073
Significant Other Observable Inputs (Level 2) [Member] | Asset-Backed Securities [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale debt securities 149,596 223,254
Significant Other Observable Inputs (Level 2) [Member] | Single issue trust preferred securities [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale debt securities 12,984 12,658
Significant Other Observable Inputs (Level 2) [Member] | Other corporate securities [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale debt securities 167,102 227,685
Significant Other Observable Inputs (Level 2) [Member] | Financial Services Industry [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale equity securities 0 5,404
Significant Other Observable Inputs (Level 2) [Member] | Fixed Income Mutual Funds [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale equity securities 0 0
Significant Other Observable Inputs (Level 2) [Member] | Interest Rate Swap Contracts [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative financial assets 543 316
Significant Other Observable Inputs (Level 2) [Member] | Forward loan sales commitments [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative financial assets 0 0
Significant Other Observable Inputs (Level 2) [Member] | Interest Rate Lock Commitments [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative financial assets 0 0
Significant Other Observable Inputs (Level 2) [Member] | TBA Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative financial assets 0  
Derivative financial liabilities 0 0
Significant Other Observable Inputs (Level 2) [Member] | Equity Mutual Funds [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale equity securities 0 0
Significant Unobservable Inputs (Level 3) [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Loans held for sale 17,712 31,277
Derivative financial assets 631 473
Derivative financial liabilities 0 0
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale debt securities 0 0
Available for sale equity securities 0 0
Loans held for sale 17,712 31,277
Derivative financial assets 631 473
Derivative financial liabilities 0 70
Significant Unobservable Inputs (Level 3) [Member] | U.S. Treasury securities and obligations of U.S. Government corporations and agencies [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale debt securities 0 0
Significant Unobservable Inputs (Level 3) [Member] | State and Political Subdivisions [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale debt securities 0 0
Significant Unobservable Inputs (Level 3) [Member] | Residential Mortgage-Backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Agency [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale debt securities 0 0
Significant Unobservable Inputs (Level 3) [Member] | Residential Mortgage-Backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Non-Agency [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale debt securities 0 0
Significant Unobservable Inputs (Level 3) [Member] | Commercial Mortgage-Backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Agency [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale debt securities 0 0
Significant Unobservable Inputs (Level 3) [Member] | Asset-Backed Securities [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale debt securities 0 0
Significant Unobservable Inputs (Level 3) [Member] | Single issue trust preferred securities [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale debt securities 0 0
Significant Unobservable Inputs (Level 3) [Member] | Other corporate securities [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale debt securities 0 0
Significant Unobservable Inputs (Level 3) [Member] | Financial Services Industry [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale equity securities 0 0
Significant Unobservable Inputs (Level 3) [Member] | Fixed Income Mutual Funds [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale equity securities 0 0
Significant Unobservable Inputs (Level 3) [Member] | Interest Rate Swap Contracts [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative financial assets 0 0
Significant Unobservable Inputs (Level 3) [Member] | Forward loan sales commitments [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative financial assets 13 15
Significant Unobservable Inputs (Level 3) [Member] | Interest Rate Lock Commitments [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative financial assets 30 458
Significant Unobservable Inputs (Level 3) [Member] | TBA Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivative financial assets 588  
Derivative financial liabilities 0 70
Significant Unobservable Inputs (Level 3) [Member] | Equity Mutual Funds [Member] | Fair Value, Measurements, Recurring [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Available for sale equity securities $ 0 $ 0