v3.26.1
Investment Securities, Equity Securities with Readily Determinable Fair Values and Other Investments - Contractual Maturities and Estimated Fair Values (Details) - USD ($)
3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Dec. 31, 2025
Amortized Cost          
Due in one year or less, held-to-maturity debt securities amortized cost $ 1,200,000   $ 1,200,000    
Due after one year through five years, held-to-maturity debt securities amortized cost 3,200,000   3,200,000    
Amortized cost, held-to-maturity debt securities 4,400,000   4,400,000   $ 4,400,000
Fair Value          
Due in one year or less, held-to-maturity debt securities, Estimated fair value 1,200,000   1,200,000    
Due after one year through five years, held-to-maturity debt securities, Estimated fair value 3,200,000   3,200,000    
Estimated fair value 4,400,000   4,400,000   4,400,000
Available-for-sale debt securities amortized cost disclosures          
Due after five years through ten years, available-for-sale debt securities amortized cost 2,865,000   2,865,000    
Due after ten years, available-for-sale debt securities amortized cost 134,778,000   134,778,000    
Residential mortgage-backed securities, available-for-sale debt securities amortized cost 5,301,739,000   5,301,739,000    
Amortized cost, Available-for-sale securities 5,439,382,000   5,439,382,000   5,281,090,000
Available for sale debt securities, Estimated Fair Value Disclosures          
Due after five years through ten years, available-for-sale debt securities, Estimated Fair Value 2,866,000   2,866,000    
Due after ten years, available-for-sale debt securities, Estimated Fair Value 130,050,000   130,050,000    
Residential mortgage-backed securities, available-for-sale debt securities, Estimated Fair Value 4,953,967,000   4,953,967,000    
Estimated fair value, Available for sale securities 5,086,883,000   5,086,883,000   $ 4,966,268,000
Available for sale debt securities, Estimated Fair Value Disclosures          
Proceeds from sales and calls of available for sale securities 0 $ 730,000 3,345,000 $ 4,235,000  
Proceeds from sales of mortgage-backed securities 0 0 0 0  
Gross gains realized on sales 0 0 0 0  
Gross losses realized on sales 0 $ 0 0 $ 0  
Collateral pledged          
Available-for-sale debt securities amortized cost disclosures          
Amortized cost, Available-for-sale securities 1,638,689,000   1,638,689,000    
Available for sale debt securities, Estimated Fair Value Disclosures          
Fair value of available for sale investment securities pledged $ 1,472,501,000   $ 1,472,501,000