v3.26.3
Investment Securities - Securities Available for Sale (Details) - USD ($)
$ in Thousands
Sep. 30, 2026
Dec. 31, 2025
Debt Securities, Available-for-sale [Line Items]    
Amortized cost $ 3,535,205 $ 3,266,829
Gross unrealized gains 7,030 31,608
Gross unrealized losses (257,885) (133,681)
Fair value 3,284,350 3,164,756
U.S. Treasury obligations    
Debt Securities, Available-for-sale [Line Items]    
Amortized cost 191,896 274,500
Gross unrealized gains 2 190
Gross unrealized losses (6,556) (7,946)
Fair value 185,342 266,744
Government-agency obligations    
Debt Securities, Available-for-sale [Line Items]    
Amortized cost 26,673 32,693
Gross unrealized gains 597 877
Gross unrealized losses (64) (31)
Fair value 27,206 33,539
Mortgage-backed securities    
Debt Securities, Available-for-sale [Line Items]    
Amortized cost 3,051,193 2,705,346
Gross unrealized gains 1,012 23,454
Gross unrealized losses (233,760) (116,453)
Fair value 2,818,445 2,612,347
Asset-backed securities    
Debt Securities, Available-for-sale [Line Items]    
Amortized cost 34,256 41,619
Gross unrealized gains 427 409
Gross unrealized losses (207) (267)
Fair value 34,476 41,761
State and municipal obligations    
Debt Securities, Available-for-sale [Line Items]    
Amortized cost 118,869 119,173
Gross unrealized gains 19 1,249
Gross unrealized losses (14,985) (7,423)
Fair value 103,903 112,999
Corporate obligations    
Debt Securities, Available-for-sale [Line Items]    
Amortized cost 112,318 93,498
Gross unrealized gains 4,973 5,429
Gross unrealized losses (2,313) (1,561)
Fair value $ 114,978 $ 97,366