v3.26.1
INVESTMENT SECURITIES - Additional Information (Details)
 3 Months Ended 6 Months Ended
Jun. 30, 2026
USD ($)
security
Jun. 30, 2025
USD ($)
Jun. 30, 2026
USD ($)
security
Jun. 30, 2025
USD ($)
Dec. 31, 2025
USD ($)
Summary of Investment Holdings [Line Items]          
Transferred from available-for-sale to held-for-maturity $ 86,900,000   $ 86,900,000   $ 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 $ 69,600,000   $ 69,600,000   70,100,000
Number of securities in security portfolio | security 2,989   2,989    
Number of securities in unrealized loss position | security 2,297   2,297    
Equity securities, at fair value $ 131,113,000   $ 131,113,000   128,857,000
(Losses) gains on equity securities 300,000 $ (600,000) (400,000) $ (500,000)  
Impairments on equity securities without readily determinable fair value 0 $ 0 0 $ 0  
Balance Sheet Location: us-gaap:OtherAssets          
Summary of Investment Holdings [Line Items]          
Equity securities without readily determinable fair value 1,100,000,000   1,100,000,000   1,000,000,000.0
Balance Sheet Location: us-gaap:OtherAssets | Partnership Interest          
Summary of Investment Holdings [Line Items]          
Equity securities without readily determinable fair value 645,500,000   645,500,000   606,500,000
Balance Sheet Location: us-gaap:OtherAssets | Initiatives in Low-to-Moderate Income Neighborhoods          
Summary of Investment Holdings [Line Items]          
Equity securities without readily determinable fair value $ 428,900,000   $ 428,900,000   $ 410,000,000.0