v3.26.1
Investment Securities - Schedule of Securities With Unrealized Losses (Details) - USD ($)
$ in Thousands
Jun. 30, 2026
Dec. 31, 2025
Debt Securities, Available-for-sale [Line Items]    
Available-for-sale, less than 12 months, estimated fair value $ 227,603 $ 23,309
Available-for-sale, less than 12 months, gross unrealized losses (901) (1,060)
Available-for-sale, 12 months or more, estimated fair value 2,520,183 2,636,931
Available-for-sale, 12 months or more, gross unrealized losses (362,148) (381,857)
Available-for-sale, total, estimated fair value 2,747,786 2,660,240
Available-for-sale, total, gross unrealized losses (363,049) (382,917)
U.S. Government agencies    
Debt Securities, Available-for-sale [Line Items]    
Available-for-sale, less than 12 months, estimated fair value 0 2,247
Available-for-sale, less than 12 months, gross unrealized losses 0 (17)
Available-for-sale, 12 months or more, estimated fair value 43,291 43,767
Available-for-sale, 12 months or more, gross unrealized losses (587) (603)
Available-for-sale, total, estimated fair value 43,291 46,014
Available-for-sale, total, gross unrealized losses (587) (620)
Mortgage-backed securities    
Debt Securities, Available-for-sale [Line Items]    
Available-for-sale, less than 12 months, estimated fair value 210,440 15,305
Available-for-sale, less than 12 months, gross unrealized losses (871) (74)
Available-for-sale, 12 months or more, estimated fair value 1,559,771 1,672,723
Available-for-sale, 12 months or more, gross unrealized losses (192,327) (189,686)
Available-for-sale, total, estimated fair value 1,770,211 1,688,028
Available-for-sale, total, gross unrealized losses (193,198) (189,760)
State and political subdivisions    
Debt Securities, Available-for-sale [Line Items]    
Available-for-sale, less than 12 months, estimated fair value 7,227 5,757
Available-for-sale, less than 12 months, gross unrealized losses (14) (969)
Available-for-sale, 12 months or more, estimated fair value 835,710 824,265
Available-for-sale, 12 months or more, gross unrealized losses (165,522) (186,123)
Available-for-sale, total, estimated fair value 842,937 830,022
Available-for-sale, total, gross unrealized losses (165,536) (187,092)
Other securities    
Debt Securities, Available-for-sale [Line Items]    
Available-for-sale, less than 12 months, estimated fair value 9,936 0
Available-for-sale, less than 12 months, gross unrealized losses (16) 0
Available-for-sale, 12 months or more, estimated fair value 81,411 96,176
Available-for-sale, 12 months or more, gross unrealized losses (3,712) (5,445)
Available-for-sale, total, estimated fair value 91,347 96,176
Available-for-sale, total, gross unrealized losses $ (3,728) $ (5,445)