v3.26.1
Investment Securities - Amortized Cost and Estimated Fair Value of Securities Contractual Maturity (Details) - USD ($)
$ in Thousands
Mar. 31, 2026
Dec. 31, 2025
Amortized Cost    
Due in one year or less, Amortized Cost $ 56,714  
Due in one year or less, Amortized Cost 4,953  
Due after one year through five years, Amortized Cost 233,601  
Due after one year through five years, Amortized Cost 120,587  
Due after five years through ten years, Amortized Cost 384,518  
Due after five years through ten years, Amortized Cost 383,180  
Due after ten years, Amortized Cost 736,666  
Due after ten years, Amortized Cost 637,203  
Amortized Cost 3,038,388 $ 3,088,820
Amortized Cost 1,258,640 1,261,267
Estimated Fair Value    
Due in one year or less, Estimated Fair Value 56,147  
Due in one year or less, Estimated Fair Value 4,918  
Due after one year through five years, Estimated Fair Value 223,610  
Due after one year through five years, Estimated Fair Value 116,202  
Due after five years through ten years, Estimated Fair Value 367,430  
Due after five years through ten years, Estimated Fair Value 353,219  
Due after ten years, Estimated Fair Value 681,433  
Due after ten years, Estimated Fair Value 561,929  
Total, Estimated Fair Value 2,803,847 2,871,931
Estimated Fair Value 1,144,994 1,161,052
U.S. government-sponsored mortgage-backed securities    
Amortized Cost    
Securities not due at a single maturity date, Amortized Cost 1,320,400  
Securities not due at a single maturity date, Amortized Cost 112,717  
Amortized Cost 1,320,400 1,345,469
Amortized Cost 112,717 114,813
Estimated Fair Value    
Securities not due at a single maturity date, Estimated Fair Value 1,177,874  
Securities not due at a single maturity date, Estimated Fair Value 108,726  
Total, Estimated Fair Value 1,177,874 1,212,948
Estimated Fair Value 108,726 111,955
Private mortgage-backed securities    
Amortized Cost    
Securities not due at a single maturity date, Amortized Cost 150,637  
Securities not due at a single maturity date, Amortized Cost 0  
Amortized Cost 150,637 152,578
Estimated Fair Value    
Securities not due at a single maturity date, Estimated Fair Value 142,527  
Securities not due at a single maturity date, Estimated Fair Value 0  
Total, Estimated Fair Value 142,527 145,720
Non-government-sponsored asset backed securities    
Amortized Cost    
Securities not due at a single maturity date, Amortized Cost 155,852  
Securities not due at a single maturity date, Amortized Cost 0  
Amortized Cost 155,852 158,446
Estimated Fair Value    
Securities not due at a single maturity date, Estimated Fair Value 154,826  
Securities not due at a single maturity date, Estimated Fair Value 0  
Total, Estimated Fair Value $ 154,826 $ 157,844