v3.26.1
Investment Securities Schedule of Amortized Cost and Fair Values of Debt Securities by Contractual Maturities (Details) - USD ($)
$ in Thousands
Jun. 30, 2026
Dec. 31, 2025
Amortized Cost    
Due in one year or less $ 6,530  
Due from one year to five years 88,012  
Due from five years to ten years 221,810  
Due after ten years 825,680  
Amortized cost, before securities without debt maturities 1,142,032  
Amortized Cost 3,800,886  
Estimated Fair Value    
Due in one year or less 6,486  
Due from one year to five years 87,206  
Due from five years to ten years 219,079  
Due after ten years 710,759  
Available for sale securities, debt maturities, before securities without single maturities 1,023,530  
Estimated Fair Value 3,561,050 $ 3,407,859
Amortized Cost    
Due in one year or less 0  
Due from one year to five years 0  
Due from five years to ten years 0  
Due after ten years 0  
Debt securities, held-to-maturity, maturity, allocated and single maturity date, amortized cost, total 0  
Amortized Cost, Held to Maturity 1,561,709 1,425,885
Estimated Fair Value    
Due in one year or less 0  
Due from one year to five years 0  
Due from five years to ten years 0  
Due after ten years 0  
Debt securities, held-to-maturity, maturity, Allocated and single maturity date, fair value 0  
Estimated Fair Value, Held to Maturity 1,393,738 1,267,578
Mortgage-Backed Securities [Member]    
Amortized Cost    
Available-for-sale securities, amortized cost without single maturity date 786,030  
Amortized Cost 786,030 781,966
Estimated Fair Value    
Available-for-sale securities, debt maturities, without single maturity date, fair value 765,528  
Estimated Fair Value 765,528 766,717
Amortized Cost    
Debt securities, held-to-maturity, maturity, without single maturity date, amortized cost 516,680  
Amortized Cost, Held to Maturity 516,680 573,636
Estimated Fair Value    
Debt securities, held-to-maturity, maturity, without single maturity date, fair value 474,895  
Estimated Fair Value, Held to Maturity 474,895 534,521
Commercial Mortgage Backed Securities [Member]    
Amortized Cost    
Available-for-sale securities, amortized cost without single maturity date 679,928  
Amortized Cost 679,928 647,375
Estimated Fair Value    
Available-for-sale securities, debt maturities, without single maturity date, fair value 587,673  
Estimated Fair Value 587,673 559,450
Amortized Cost    
Debt securities, held-to-maturity, maturity, without single maturity date, amortized cost 882,010  
Amortized Cost, Held to Maturity 882,010 852,249
Estimated Fair Value    
Debt securities, held-to-maturity, maturity, without single maturity date, fair value 758,664  
Estimated Fair Value, Held to Maturity 758,664 733,057
Collateralized Mortgage Obligations [Member]    
Amortized Cost    
Available-for-sale securities, amortized cost without single maturity date 1,192,896  
Amortized Cost 1,192,896 1,034,548
Estimated Fair Value    
Available-for-sale securities, debt maturities, without single maturity date, fair value 1,184,319  
Estimated Fair Value 1,184,319 $ 1,040,078
Amortized Cost    
Debt securities, held-to-maturity, maturity, without single maturity date, amortized cost 163,019  
Amortized Cost, Held to Maturity 163,019  
Estimated Fair Value    
Debt securities, held-to-maturity, maturity, without single maturity date, fair value 160,179  
Estimated Fair Value, Held to Maturity $ 160,179