v3.26.1
Investment Securities - Narrative (Details)
 6 Months Ended
Jun. 30, 2026
USD ($)
security
Jun. 30, 2025
USD ($)
Dec. 31, 2025
USD ($)
security
Investment Securities      
Investment securities available-for-sale $ 1,761,297,000   $ 1,688,768,000
Debt securities, unrealized gain (loss) (47,400,000)   (27,500,000)
AFS, debt securities, unrealized loss position $ 1,200,000,000   $ 552,900,000
Percentage of securities in unrealized loss positions, available-for-sale securities 70.80%   32.70%
AFS, debt securities, unrealized loss position, accumulated loss $ 56,700,000   $ 44,700,000
Accrued interest receivable $ 7,700,000   7,200,000
Number of days past due to be placed in nonaccrual status 90 days    
Purchases of securities available-for-sale $ 280,425,000 $ 11,737,000  
Estimated fair value of debt securities have right to call or prepay the obligations 332,800,000   965,200,000
Estimated fair value of debt securities that have right to call or prepay the obligations, scheduled maturities of less than one year     12,400,000
Estimated fair value of debt securities have right to call or prepay the obligations, scheduled maturities of after one year through five years 112,200,000   111,400,000
Estimated fair value of debt securities have right to call or prepay the obligations, scheduled maturities after six years through ten years 119,100,000   157,100,000
Estimated fair value of debt securities have right to call or prepay the obligations, scheduled maturities of which is after ten years 101,500,000   684,300,000
US Government Sponsored Enterprises      
Investment Securities      
Investment securities available-for-sale 431,500,000   285,400,000
GSE debentures      
Investment Securities      
Investment securities available-for-sale 186,212,000   173,677,000
Debt securities, unrealized gain (loss) $ (13,100,000)   $ (11,800,000)
AFS number of positions | security 32   38
Number of securities in unrealized loss positions | security 26   17
Purchases of securities available-for-sale $ 40,000,000.0 0  
GSE CMOs      
Investment Securities      
Investment securities available-for-sale 658,000,000.0   $ 496,600,000
Debt securities, unrealized gain (loss) $ (14,300,000)   $ (3,900,000)
AFS number of positions | security 147   136
Number of securities in unrealized loss positions | security 133   57
Purchases of securities available-for-sale $ 210,800,000 0  
GSE MBSs      
Investment Securities      
Investment securities available-for-sale 304,800,000   $ 325,700,000
Debt securities, unrealized gain (loss) $ (12,400,000)   $ (8,700,000)
AFS number of positions | security 189   194
Number of securities in unrealized loss positions | security 119   85
Purchases of securities available-for-sale $ 0 0  
Municipal obligations      
Investment Securities      
Investment securities available-for-sale 227,249,000   $ 240,216,000
Debt securities, unrealized gain (loss) $ 6,900,000   $ 8,300,000
AFS number of positions | security 232   242
Number of securities in unrealized loss positions | security 19   12
Purchases of securities available-for-sale $ 967,400 1,300,000  
Corporate debt obligations      
Investment Securities      
Investment securities available-for-sale 25,135,000   $ 40,023,000
Debt securities, unrealized gain (loss) $ 600,000   $ 800,000
AFS number of positions | security 17   16
Number of securities in unrealized loss positions | security 4   2
Purchases of securities available-for-sale $ 0 0  
U.S. Treasury bonds      
Investment Securities      
Investment securities available-for-sale 359,400,000   $ 412,000,000.0
Debt securities, unrealized gain (loss) $ (15,100,000)   $ (12,200,000)
AFS number of positions | security 44   54
Number of securities in unrealized loss positions | security 34   25
Purchases of securities available-for-sale $ 29,500,000 $ 9,900,000  
Foreign government obligations      
Investment Securities      
Investment securities available-for-sale $ 500,000   $ 500,000
AFS number of positions | security 1   1
Purchases of securities available-for-sale $ 0    
Collateral Pledged      
Investment Securities      
Available for sale securities pledged as collateral 1,500,000,000   $ 1,200,000,000
Outstanding borrowings $ 0   $ 0