v3.26.1
Investment Securities - Narrative (Details)
 3 Months Ended
Mar. 31, 2026
USD ($)
security
Mar. 31, 2025
USD ($)
Dec. 31, 2025
USD ($)
security
Investment Securities      
Investment securities available-for-sale $ 1,718,710,000   $ 1,688,768,000
Debt securities, unrealized gain (loss) (42,700,000)   (27,500,000)
AFS, debt securities, unrealized loss position $ 1,000,000,000.0   $ 552,900,000
Percentage of securities in unrealized loss positions, available-for-sale securities 59.50%   32.70%
AFS, debt securities, unrealized loss position, accumulated loss $ 51,000,000.0   $ 44,700,000
Accrued interest receivable $ 8,000,000.0   7,200,000
Number of days past due to be placed in nonaccrual status 90 days    
Purchases of securities available-for-sale $ 129,139,000 $ 651,000  
Estimated fair value of debt securities have right to call or prepay the obligations 951,500,000   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 103,900,000   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 386,800,000   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 201,200,000   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 259,600,000   684,300,000
US Government Sponsored Enterprises      
Investment Securities      
Investment securities available-for-sale 345,000,000.0   285,400,000
GSE debentures      
Investment Securities      
Investment securities available-for-sale 178,596,000   173,677,000
Debt securities, unrealized gain (loss) $ (12,400,000)   $ (11,800,000)
AFS number of positions | security 31   38
Number of securities in unrealized loss positions | security 21   17
Purchases of securities available-for-sale $ 20,000,000.0 0  
GSE CMOs      
Investment Securities      
Investment securities available-for-sale 553,600,000   $ 496,600,000
Debt securities, unrealized gain (loss) $ (10,300,000)   $ (3,900,000)
AFS number of positions | security 144   136
Number of securities in unrealized loss positions | security 122   57
Purchases of securities available-for-sale $ 79,600,000 0  
GSE MBSs      
Investment Securities      
Investment securities available-for-sale 316,100,000   $ 325,700,000
Debt securities, unrealized gain (loss) $ (10,100,000)   $ (8,700,000)
AFS number of positions | security 193   194
Number of securities in unrealized loss positions | security 98   85
Purchases of securities available-for-sale $ 0 0.0  
Municipal obligations      
Investment Securities      
Investment securities available-for-sale 228,488,000   $ 240,216,000
Debt securities, unrealized gain (loss) $ 3,100,000   $ 8,300,000
AFS number of positions | security 238   242
Number of securities in unrealized loss positions | security 43   12
Purchases of securities available-for-sale $ 32,000.0 200,000  
Corporate debt obligations      
Investment Securities      
Investment securities available-for-sale 35,994,000   $ 40,023,000
Debt securities, unrealized gain (loss) $ 600,000   $ 800,000
AFS number of positions | security 19   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 405,400,000   $ 412,000,000.0
Debt securities, unrealized gain (loss) $ (13,700,000)   $ (12,200,000)
AFS number of positions | security 51   54
Number of securities in unrealized loss positions | security 30   25
Purchases of securities available-for-sale $ 29,500,000 $ 0  
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 1,300,000,000   $ 1,200,000,000
Outstanding borrowings $ 0   $ 0