v3.26.1
Fair Value Measurement - Schedule of Fair Value of Assets and Liabilities Measured on Recurring and Nonrecurring Basis (Detail) - USD ($)
$ in Thousands
Jun. 30, 2026
Dec. 31, 2025
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Equity securities $ 19,060 $ 30,809
Available-for-sale debt securities 3,312,972 3,288,332
Loans held for sale 57,318 87,454
Other real estate owned and repossessed assets 1,391 907
Recurring Fair Value Measurements [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Equity securities 19,060 30,809
Available-for-sale debt securities 3,312,972 3,288,332
Loans held for sale 57,318 87,454
Other assets - interest rate swaps 54,650 63,144
Total assets recurring fair value measurements 3,444,000 3,469,739
Other liabilities - interest rate swaps 55,492 64,181
Total liabilities recurring fair value measurements 55,492 64,181
Nonrecurring Fair Value Measurements [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Collateral dependent loans 26,513 20,400
Other real estate owned and repossessed assets 1,391 907
Total assets recurring fair value measurements 27,904 21,307
U.S. Treasury [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities 195,957 196,857
U.S. Treasury [Member] | Recurring Fair Value Measurements [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities 195,957 196,857
U.S. Government Sponsored Entities and Agencies [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities 211,065 222,997
U.S. Government Sponsored Entities and Agencies [Member] | Recurring Fair Value Measurements [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities 211,065 222,997
Residential Mortgage-Backed Securities and Collateralized Mortgage Obligations of Government Sponsored Entities and Agencies [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities 2,667,319 2,610,448
Residential Mortgage-Backed Securities and Collateralized Mortgage Obligations of Government Sponsored Entities and Agencies [Member] | Recurring Fair Value Measurements [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities 2,667,319 2,610,448
Commercial Mortgage-Backed Securities and Collateralized Mortgage Obligations of Government Sponsored Entities and Agencies [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities 54,600 63,615
Commercial Mortgage-Backed Securities and Collateralized Mortgage Obligations of Government Sponsored Entities and Agencies [Member] | Recurring Fair Value Measurements [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities 54,600 63,615
Asset Backed Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities 64,994 68,935
Asset Backed Securities [Member] | Recurring Fair Value Measurements [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities 64,994 68,935
Obligations of States and Political Subdivisions [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities 77,432 73,188
Obligations of States and Political Subdivisions [Member] | Recurring Fair Value Measurements [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities 77,432 73,188
Corporate Debt Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities 41,605 52,292
Corporate Debt Securities [Member] | Recurring Fair Value Measurements [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities 41,605 52,292
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Equity securities 19,060 30,809
Available-for-sale debt securities 195,957 196,857
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Recurring Fair Value Measurements [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Equity securities 19,060 30,809
Available-for-sale debt securities 195,957 196,857
Total assets recurring fair value measurements 215,017 227,666
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | U.S. Treasury [Member] | Recurring Fair Value Measurements [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities 195,957 196,857
Significant Other Observable Inputs (Level 2) [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities 3,114,797 3,089,190
Loans held for sale 57,318 87,454
Other assets - interest rate swaps 54,650 63,144
Other liabilities - interest rate swaps 55,492 64,181
Significant Other Observable Inputs (Level 2) [Member] | Recurring Fair Value Measurements [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities 3,114,797 3,089,190
Loans held for sale 57,318 87,454
Other assets - interest rate swaps 54,650 63,144
Total assets recurring fair value measurements 3,226,765 3,239,788
Other liabilities - interest rate swaps 55,492 64,181
Total liabilities recurring fair value measurements 55,492 64,181
Significant Other Observable Inputs (Level 2) [Member] | U.S. Government Sponsored Entities and Agencies [Member] | Recurring Fair Value Measurements [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities 211,065 222,997
Significant Other Observable Inputs (Level 2) [Member] | Residential Mortgage-Backed Securities and Collateralized Mortgage Obligations of Government Sponsored Entities and Agencies [Member] | Recurring Fair Value Measurements [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities 2,667,319 2,610,448
Significant Other Observable Inputs (Level 2) [Member] | Commercial Mortgage-Backed Securities and Collateralized Mortgage Obligations of Government Sponsored Entities and Agencies [Member] | Recurring Fair Value Measurements [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities 54,600 63,615
Significant Other Observable Inputs (Level 2) [Member] | Asset Backed Securities [Member] | Recurring Fair Value Measurements [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities 64,994 68,935
Significant Other Observable Inputs (Level 2) [Member] | Obligations of States and Political Subdivisions [Member] | Recurring Fair Value Measurements [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities 75,214 70,903
Significant Other Observable Inputs (Level 2) [Member] | Corporate Debt Securities [Member] | Recurring Fair Value Measurements [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities 41,605 52,292
Significant Unobservable Inputs (Level 3) [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities 2,218 2,285
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities 2,218 2,285
Total assets recurring fair value measurements 2,218 2,285
Significant Unobservable Inputs (Level 3) [Member] | Nonrecurring Fair Value Measurements [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Collateral dependent loans 26,513 20,400
Other real estate owned and repossessed assets 1,391 907
Total assets recurring fair value measurements 27,904 21,307
Significant Unobservable Inputs (Level 3) [Member] | Obligations of States and Political Subdivisions [Member] | Recurring Fair Value Measurements [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities $ 2,218 $ 2,285