v3.26.1
Fair Value Measurement of Assets and Liabilities - Recurring and Non-Recurring Basis (Details) - USD ($)
$ in Thousands
Jun. 30, 2026
Dec. 31, 2025
Investment securities:    
Equity securities $ 88,541 $ 82,774
Trading debt securities 26,493 0
Available for sale debt securities:    
Available for sale debt securities 4,292,148 4,202,218
Loans held for sale 4,940 8,212
Non-recurring fair value measurements:    
Unpaid principal balances of loans held for sale 4,900 8,100
Specific valuation allowance allocations 90,500 82,000
U.S. Treasury securities    
Available for sale debt securities:    
Available for sale debt securities 226,998 228,487
U.S. government agency securities    
Available for sale debt securities:    
Available for sale debt securities 38,699 39,944
Obligations of states and political subdivisions    
Available for sale debt securities:    
Available for sale debt securities 197,354 193,380
Residential mortgage-backed securities    
Available for sale debt securities:    
Available for sale debt securities 3,589,700 3,514,078
Corporate and other debt securities    
Available for sale debt securities:    
Available for sale debt securities 239,397 226,329
Recurring fair value measurements    
Investment securities:    
Trading debt securities 26,493  
Available for sale debt securities:    
Available for sale debt securities 4,292,148 4,202,218
Loans held for sale 4,940 8,212
Other assets 265,370 182,673
Total assets 4,621,376 4,426,506
Liabilities    
Other liabilities 264,214 184,162
Total liabilities 264,214 184,162
Recurring fair value measurements | U.S. Treasury securities    
Available for sale debt securities:    
Available for sale debt securities 226,998 228,487
Recurring fair value measurements | U.S. government agency securities    
Available for sale debt securities:    
Available for sale debt securities 38,699 39,944
Recurring fair value measurements | Obligations of states and political subdivisions    
Available for sale debt securities:    
Available for sale debt securities 197,354 193,380
Recurring fair value measurements | Residential mortgage-backed securities    
Available for sale debt securities:    
Available for sale debt securities 3,589,700 3,514,078
Recurring fair value measurements | Corporate and other debt securities    
Available for sale debt securities:    
Available for sale debt securities 239,397 226,329
Non-recurring fair value measurements    
Non-recurring fair value measurements:    
Collateral dependent loans 113,921 105,107
Foreclosed assets 4,868 5,680
Total 118,789 110,787
Fair Value, Inputs, Level 1, Level 2, and Level 3 | Recurring fair value measurements    
Investment securities:    
Equity securities 23,186 23,293
Quoted Prices in Active Markets for Identical Assets (Level 1) | Recurring fair value measurements    
Investment securities:    
Equity securities 23,186 23,293
Trading debt securities 26,493  
Available for sale debt securities:    
Available for sale debt securities 226,998 228,487
Loans held for sale 0 0
Other assets 0 0
Total assets 276,677 251,780
Liabilities    
Other liabilities 0 0
Total liabilities 0 0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Recurring fair value measurements | U.S. Treasury securities    
Available for sale debt securities:    
Available for sale debt securities 226,998 228,487
Quoted Prices in Active Markets for Identical Assets (Level 1) | Recurring fair value measurements | U.S. government agency securities    
Available for sale debt securities:    
Available for sale debt securities 0 0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Recurring fair value measurements | Obligations of states and political subdivisions    
Available for sale debt securities:    
Available for sale debt securities 0 0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Recurring fair value measurements | Residential mortgage-backed securities    
Available for sale debt securities:    
Available for sale debt securities 0 0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Recurring fair value measurements | Corporate and other debt securities    
Available for sale debt securities:    
Available for sale debt securities 0 0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Non-recurring fair value measurements    
Non-recurring fair value measurements:    
Collateral dependent loans 0 0
Foreclosed assets 0 0
Total 0 0
Significant Other Observable Inputs (Level 2) | Recurring fair value measurements    
Investment securities:    
Equity securities 0 0
Trading debt securities 0  
Available for sale debt securities:    
Available for sale debt securities 4,065,150 3,973,731
Loans held for sale 4,940 8,212
Other assets 265,370 182,673
Total assets 4,335,460 4,164,616
Liabilities    
Other liabilities 264,214 184,162
Total liabilities 264,214 184,162
Significant Other Observable Inputs (Level 2) | Recurring fair value measurements | U.S. Treasury securities    
Available for sale debt securities:    
Available for sale debt securities 0 0
Significant Other Observable Inputs (Level 2) | Recurring fair value measurements | U.S. government agency securities    
Available for sale debt securities:    
Available for sale debt securities 38,699 39,944
Significant Other Observable Inputs (Level 2) | Recurring fair value measurements | Obligations of states and political subdivisions    
Available for sale debt securities:    
Available for sale debt securities 197,354 193,380
Significant Other Observable Inputs (Level 2) | Recurring fair value measurements | Residential mortgage-backed securities    
Available for sale debt securities:    
Available for sale debt securities 3,589,700 3,514,078
Significant Other Observable Inputs (Level 2) | Recurring fair value measurements | Corporate and other debt securities    
Available for sale debt securities:    
Available for sale debt securities 239,397 226,329
Significant Other Observable Inputs (Level 2) | Non-recurring fair value measurements    
Non-recurring fair value measurements:    
Collateral dependent loans 0 0
Foreclosed assets 0 0
Total 0 0
Significant Unobservable Inputs (Level 3) | Recurring fair value measurements    
Investment securities:    
Equity securities 0 0
Trading debt securities 0  
Available for sale debt securities:    
Available for sale debt securities 0 0
Loans held for sale 0 0
Other assets 0 0
Total assets 0 0
Liabilities    
Other liabilities 0 0
Total liabilities 0 0
Significant Unobservable Inputs (Level 3) | Recurring fair value measurements | U.S. Treasury securities    
Available for sale debt securities:    
Available for sale debt securities 0 0
Significant Unobservable Inputs (Level 3) | Recurring fair value measurements | U.S. government agency securities    
Available for sale debt securities:    
Available for sale debt securities 0 0
Significant Unobservable Inputs (Level 3) | Recurring fair value measurements | Obligations of states and political subdivisions    
Available for sale debt securities:    
Available for sale debt securities 0 0
Significant Unobservable Inputs (Level 3) | Recurring fair value measurements | Residential mortgage-backed securities    
Available for sale debt securities:    
Available for sale debt securities 0 0
Significant Unobservable Inputs (Level 3) | Recurring fair value measurements | Corporate and other debt securities    
Available for sale debt securities:    
Available for sale debt securities 0 0
Significant Unobservable Inputs (Level 3) | Non-recurring fair value measurements    
Non-recurring fair value measurements:    
Collateral dependent loans 113,921 105,107
Foreclosed assets 4,868 5,680
Total 118,789 110,787
NAV | Recurring fair value measurements    
Investment securities:    
Equity securities $ 9,239 $ 10,110