v3.26.1
Fair Value - Financial Assets and Liabilities Measured at Fair Value Recurring Basis (Details) - USD ($)
$ in Thousands
Mar. 31, 2026
Dec. 31, 2025
Mar. 31, 2025
Dec. 31, 2024
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Securities available for sale $ 1,913,835 $ 1,876,830    
Loans held for sale (LHFS) 291,122 278,789    
Mortgage servicing rights (MSR) 136,796 131,289 $ 134,395 $ 139,317
U.S. Treasury Securities [Member]        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Securities available for sale 221,733 208,948    
U.S. Government Agency Obligations [Member]        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Securities available for sale 70,255 70,849    
Recurring Basis [Member]        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Securities available for sale 1,913,835 1,876,830    
Loans held for sale (LHFS) 291,122 278,789    
Mortgage servicing rights (MSR) 136,796 131,289    
Other assets - derivatives 12,444 16,235    
Other liabilities - derivatives $ 25,786 $ 22,832    
Derivative Asset, Statement of Financial Position [Extensible Enumeration] Other Assets Other Assets    
Derivative Liability, Statement of Financial Position [Extensible Enumeration] Other Liabilities Other Liabilities    
Recurring Basis [Member] | U.S. Treasury Securities [Member]        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Securities available for sale $ 221,733 $ 208,948    
Recurring Basis [Member] | U.S. Government Agency Obligations [Member]        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Securities available for sale 70,255 70,849    
Recurring Basis [Member] | Mortgage-Backed Securities [Member]        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Securities available for sale 1,621,847 1,597,033    
Level 1 [Member] | Recurring Basis [Member]        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Securities available for sale 221,733 208,948    
Loans held for sale (LHFS) 0 0    
Mortgage servicing rights (MSR) 0 0    
Other assets - derivatives 19 11    
Other liabilities - derivatives 5,578 1,708    
Level 1 [Member] | Recurring Basis [Member] | U.S. Treasury Securities [Member]        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Securities available for sale 221,733 208,948    
Level 1 [Member] | Recurring Basis [Member] | U.S. Government Agency Obligations [Member]        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Securities available for sale 0 0    
Level 1 [Member] | Recurring Basis [Member] | Mortgage-Backed Securities [Member]        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Securities available for sale 0 0    
Level 2 [Member] | Recurring Basis [Member]        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Securities available for sale 1,692,102 1,667,882    
Loans held for sale (LHFS) 291,122 278,789    
Mortgage servicing rights (MSR) 0 0    
Other assets - derivatives 11,538 15,226    
Other liabilities - derivatives 20,208 21,124    
Level 2 [Member] | Recurring Basis [Member] | U.S. Treasury Securities [Member]        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Securities available for sale 0 0    
Level 2 [Member] | Recurring Basis [Member] | U.S. Government Agency Obligations [Member]        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Securities available for sale 70,255 70,849    
Level 2 [Member] | Recurring Basis [Member] | Mortgage-Backed Securities [Member]        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Securities available for sale 1,621,847 1,597,033    
Level 3 [Member] | Recurring Basis [Member]        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Securities available for sale 0 0    
Loans held for sale (LHFS) 0 0    
Mortgage servicing rights (MSR) 136,796 131,289    
Other assets - derivatives 887 998    
Other liabilities - derivatives 0 0    
Level 3 [Member] | Recurring Basis [Member] | U.S. Treasury Securities [Member]        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Securities available for sale 0 0    
Level 3 [Member] | Recurring Basis [Member] | U.S. Government Agency Obligations [Member]        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Securities available for sale 0 0    
Level 3 [Member] | Recurring Basis [Member] | Mortgage-Backed Securities [Member]        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Securities available for sale $ 0 $ 0