v3.26.1
Investment Securities - Amortized Cost and Fair Value of Securities Held-to-Maturity (Details) - USD ($)
$ in Thousands
Mar. 31, 2026
Dec. 31, 2025
Mar. 31, 2025
Dec. 31, 2024
Schedule of Held-to-maturity Securities [Line Items]        
Amortized Cost $ 1,258,640 $ 1,261,267    
Allowance for Credit Losses (2,005) (2,005) $ (2,005) $ (2,005)
Net Carrying Amount 1,256,635 1,259,262    
Gross Unrealized Gains 185 471    
Gross Unrealized (Losses) (111,826) (98,681)    
Estimated Fair Value 1,144,994 1,161,052    
U.S. government-sponsored enterprises        
Schedule of Held-to-maturity Securities [Line Items]        
Amortized Cost 43,912 43,841    
Allowance for Credit Losses 0 0    
Net Carrying Amount 43,912 43,841    
Gross Unrealized Gains 0 0    
Gross Unrealized (Losses) (1,758) (1,391)    
Estimated Fair Value 42,154 42,450    
U.S. government-sponsored mortgage-backed securities        
Schedule of Held-to-maturity Securities [Line Items]        
Amortized Cost 112,717 114,813    
Allowance for Credit Losses 0 0    
Net Carrying Amount 112,717 114,813    
Gross Unrealized Gains 153 400    
Gross Unrealized (Losses) (4,144) (3,258)    
Estimated Fair Value 108,726 111,955    
State and political subdivisions        
Schedule of Held-to-maturity Securities [Line Items]        
Amortized Cost 1,102,011 1,102,613    
Allowance for Credit Losses (2,005) (2,005)    
Net Carrying Amount 1,100,006 1,100,608    
Gross Unrealized Gains 32 71    
Gross Unrealized (Losses) (105,924) (94,032)    
Estimated Fair Value $ 994,114 $ 1,006,647