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Investment Securities - Additional Information (Details)
 3 Months Ended
Mar. 31, 2025
USD ($)
security
Mar. 31, 2024
USD ($)
Dec. 31, 2024
USD ($)
Summary of Investment Holdings [Line Items]      
Transferred from available-for-sale to held-for-maturity $ 106,000,000.0   $ 110,000,000.0
Allowance for credit losses for available-for-sale debt securities $ 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
Allowance for securities held-to-maturity $ 150,000   $ 150,000
Accrued interest receivable $ 44,100,000   55,300,000
Number of securities in security portfolio | security 2,988    
Number of securities in unrealized loss position | security 2,524    
Equity securities, at fair value $ 91,650,000   91,996,000
(Losses) gains on equity securities 100,000 $ 300,000  
Impairments on equity securities without readily determinable fair value 0 0  
Downward adjustments on equity securities without readily determinable fair value 0 $ 0  
Other Assets      
Summary of Investment Holdings [Line Items]      
Equity securities without readily determinable fair value 600,300,000   609,200,000
Other Assets | Partnership Interest      
Summary of Investment Holdings [Line Items]      
Equity securities without readily determinable fair value 319,100,000   318,500,000
Other Assets | Initiatives in Low-to-Moderate Income Neighborhoods      
Summary of Investment Holdings [Line Items]      
Equity securities without readily determinable fair value $ 281,200,000   $ 290,700,000