v3.26.1
Investment Securities (Narrative) (Details) - USD ($)
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Dec. 31, 2025
Schedule of Investments [Line Items]      
Debt Securities, Available-for-sale $ 1,239,728,000   $ 688,668,000
Debt Securities, Available-for-sale, Unrealized Loss Position 884,630,000   500,500,000
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss 41,984,000   44,103,000
Securities Available-for-Sale, 12 months or longer, Fair value 412,167,000   452,648,000
Debt Securities, Available-for-sale, Allowance for Credit Loss 0   0
Debt Securities, Available-for-sale, Amortized Cost $ 1,275,376,000   729,612,000
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent 21.00%    
Debt securities available for sale, securities sold   $ 0  
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Writeoff $ 0 $ 0  
Gain on Sale of Investments 2,700,000    
Loss on Sale of Investments 1,600,000    
Debt securities available for sale, securities sold at a gain 364,800,000    
Debt securities available for sale, securities sold at a loss 217,300,000    
U.S. Government Sponsored Entities Asset-Backed Securities [Member]      
Schedule of Investments [Line Items]      
Debt Securities, Available-for-sale 833,515,000   399,964,000
Debt Securities, Available-for-sale, Unrealized Loss Position 595,777,000   356,698,000
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss 30,833,000   33,229,000
Securities Available-for-Sale, 12 months or longer, Fair value 316,000,000   335,095,000
Debt Securities, Available-for-sale, Amortized Cost 860,656,000   432,051,000
USGovernmentSponsored asset backed securities and US Treasury obligations      
Schedule of Investments [Line Items]      
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss 31,100,000    
Collateral Pledged [Member]      
Schedule of Investments [Line Items]      
Debt Securities, Available-for-sale, Restricted $ 949,500,000   $ 569,500,000