v3.26.3
Investment Securities, HTM Credit Quality Indicators (Details) - USD ($)
$ in Thousands
Sep. 30, 2026
Dec. 31, 2025
Schedule of Held-to-maturity Securities [Line Items]    
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss $ 3,462,220 $ 3,602,576
US Treasury Securities    
Schedule of Held-to-maturity Securities [Line Items]    
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss 997 996
US States and Political Subdivisions Debt Securities [Member]    
Schedule of Held-to-maturity Securities [Line Items]    
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss 1,576,827 1,628,088
Residential Mortgage-Backed Securities [Member] | US Government Sponsored-Enterprise Insured Loans    
Schedule of Held-to-maturity Securities [Line Items]    
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss 771,047 823,630
Residential Mortgage-Backed Securities [Member] | Government National Mortgage Association (GNMA) [Member]    
Schedule of Held-to-maturity Securities [Line Items]    
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss 36,181 39,123
Mortgage-backed Securities, Issued by Private Enterprises [Member]    
Schedule of Held-to-maturity Securities [Line Items]    
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss 284,928 302,817
Commercial Mortgage-Backed Securities [Member] | US Government Sponsored-Enterprise Insured Loans    
Schedule of Held-to-maturity Securities [Line Items]    
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss 752,924 763,370
Commercial Mortgage-Backed Securities [Member] | Government National Mortgage Association (GNMA) [Member]    
Schedule of Held-to-maturity Securities [Line Items]    
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss $ 39,316 $ 44,552