v3.26.3
Fair Value - Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis (Details) - USD ($)
$ in Thousands
Sep. 30, 2026
Dec. 31, 2025
Dec. 31, 2024
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value $ 214,486 $ 230,083  
Mortgage loans held for sale [1] 74,251 25,828  
Loan servicing assets 1,994 1,816 $ 5,511
Derivative assets 7,446 5,941  
Derivative liabilities 223 30  
U.S. Treasuries      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 131,312 137,236  
Municipal      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 12,683 13,897  
Corporate      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 1,443 3,404  
Asset-backed securities      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 4,615 5,026  
Mortgage-backed securities      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 64,433 70,520  
Fair Value, Measurements, Recurring      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 214,486 230,083  
Mortgage loans held for sale 14,075 25,828  
Loan servicing assets 1,994 1,816  
Derivative assets $ 7,446 $ 5,941  
Derivative Asset, Statement of Financial Position [Extensible Enumeration] Other assets Other assets  
Derivative liabilities $ 223 $ 30  
Derivative Liability, Statement of Financial Position [Extensible Enumeration] Other liabilities Other liabilities  
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value $ 131,312 $ 137,236  
Mortgage loans held for sale 0 0  
Loan servicing assets 0 0  
Derivative assets 0 0  
Derivative liabilities 0 0  
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 83,174 92,847  
Mortgage loans held for sale 14,075 25,828  
Loan servicing assets 1,994 1,816  
Derivative assets 7,446 5,941  
Derivative liabilities 223 30  
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 0 0  
Mortgage loans held for sale 0 0  
Loan servicing assets 0 0  
Derivative assets 0 0  
Derivative liabilities 0 0  
Fair Value, Measurements, Recurring | U.S. Treasuries      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 131,312 137,236  
Fair Value, Measurements, Recurring | U.S. Treasuries | Quoted Prices in Active Markets for Identical Assets (Level 1)      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 131,312 137,236  
Fair Value, Measurements, Recurring | U.S. Treasuries | Significant Other Observable Inputs (Level 2)      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 0 0  
Fair Value, Measurements, Recurring | U.S. Treasuries | Significant Unobservable Inputs (Level 3)      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 0 0  
Fair Value, Measurements, Recurring | Municipal      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 12,683 13,897  
Fair Value, Measurements, Recurring | Municipal | Quoted Prices in Active Markets for Identical Assets (Level 1)      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 0 0  
Fair Value, Measurements, Recurring | Municipal | Significant Other Observable Inputs (Level 2)      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 12,683 13,897  
Fair Value, Measurements, Recurring | Municipal | Significant Unobservable Inputs (Level 3)      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 0 0  
Fair Value, Measurements, Recurring | Corporate      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 1,443 3,404  
Fair Value, Measurements, Recurring | Corporate | Quoted Prices in Active Markets for Identical Assets (Level 1)      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 0 0  
Fair Value, Measurements, Recurring | Corporate | Significant Other Observable Inputs (Level 2)      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 1,443 3,404  
Fair Value, Measurements, Recurring | Corporate | Significant Unobservable Inputs (Level 3)      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 0 0  
Fair Value, Measurements, Recurring | Asset-backed securities      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 4,615 5,026  
Fair Value, Measurements, Recurring | Asset-backed securities | Quoted Prices in Active Markets for Identical Assets (Level 1)      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 0 0  
Fair Value, Measurements, Recurring | Asset-backed securities | Significant Other Observable Inputs (Level 2)      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 4,615 5,026  
Fair Value, Measurements, Recurring | Asset-backed securities | Significant Unobservable Inputs (Level 3)      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 0 0  
Fair Value, Measurements, Recurring | Mortgage-backed securities      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 64,433 70,520  
Fair Value, Measurements, Recurring | Mortgage-backed securities | Quoted Prices in Active Markets for Identical Assets (Level 1)      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 0 0  
Fair Value, Measurements, Recurring | Mortgage-backed securities | Significant Other Observable Inputs (Level 2)      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value 64,433 70,520  
Fair Value, Measurements, Recurring | Mortgage-backed securities | Significant Unobservable Inputs (Level 3)      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Fair Value $ 0 $ 0  
[1] Balances include held for sale transactions in connection with the Chicago Branch Sale.