v3.26.1
Debt and Equity Securities - Schedule of Amortized Cost and Estimated Fair Value of Securities (Details) - USD ($)
$ in Thousands
Jun. 30, 2026
Dec. 31, 2025
Amortized Cost    
Amortized Cost $ 3,898,763 $ 3,998,939
Fair Value    
Fair Value 3,826,284 3,951,455
Fair Value    
Fair Value 616,820 $ 654,832
Available-for-sale    
Amortized Cost    
Due within one year 0  
Due after one year through five years 0  
Due after five years through ten years 258,560  
Due after ten years 3,640,203  
Amortized Cost 3,898,763  
Fair Value    
Due within one year 0  
Due after one year through five years 0  
Due after five years through ten years 257,694  
Due after ten years 3,568,590  
Fair Value 3,826,284  
Held-to-maturity    
Amortized Cost    
Due within one year 0  
Due after one year through five years 0  
Due after five years through ten years 0  
Due after ten years 692,332  
Amortized Cost 692,332  
Fair Value    
Due within one year 0  
Due after one year through five years 0  
Due after five years through ten years 0  
Due after ten years 616,820  
Fair Value $ 616,820