v3.26.3
INVESTMENT SECURITIES - Additional Information (Details)
 3 Months Ended 9 Months Ended
Sep. 30, 2026
USD ($)
security
Sep. 30, 2025
USD ($)
Sep. 30, 2026
USD ($)
security
Sep. 30, 2025
USD ($)
Dec. 31, 2025
USD ($)
Summary of Investment Holdings [Line Items]          
Transferred from available-for-sale to held-for-maturity $ 83,000,000.0   $ 83,000,000.0   $ 94,100,000
Allowance for credit losses for available-for-sale debt securities $ 0   $ 0   $ 0
Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration] Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest   Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest   Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest
Allowance for securities held-to-maturity $ 150,000   $ 150,000   $ 150,000
Accrued interest receivable $ 59,600,000   $ 59,600,000   70,100,000
Number of securities in security portfolio | security 2,984   2,984    
Number of securities in unrealized loss position | security 2,820   2,820    
Equity securities, at fair value $ 132,263,000   $ 132,263,000   128,857,000
(Losses) gains on equity securities (900,000) $ 1,000,000.0 (1,400,000) $ 400,000  
Equity securities without readily determinable fair value 1,100,000,000   1,100,000,000   1,000,000,000.0
Impairments on equity securities without readily determinable fair value 0 $ 0 0 $ 0  
Partnership Interest          
Summary of Investment Holdings [Line Items]          
Equity securities without readily determinable fair value 654,600,000   654,600,000   606,500,000
Initiatives in Low-to-Moderate Income Neighborhoods          
Summary of Investment Holdings [Line Items]          
Equity securities without readily determinable fair value $ 435,600,000   $ 435,600,000   $ 410,000,000.0