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Investment Securities - Additional Information (Details)
 3 Months Ended
Mar. 31, 2024
USD ($)
security
Mar. 31, 2023
USD ($)
Dec. 31, 2023
USD ($)
Summary of Investment Holdings [Line Items]      
Transferred from available-for-sale to held-for-maturity $ 123,300,000   $ 127,600,000
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 $ 40,300,000   50,300,000
Number of securities in security portfolio | security 2,941    
Number of securities in unrealized loss position | security 2,702    
Equity securities, at fair value $ 84,954,000   80,372,000
Losses on equity securities 300,000 $ (800,000)  
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 474,700,000   $ 449,300,000
Other Assets | Partnership Interest      
Summary of Investment Holdings [Line Items]      
Equity securities without readily determinable fair value 270,600,000    
Other Assets | Initiatives in Low-to-Moderate Income Neighborhoods      
Summary of Investment Holdings [Line Items]      
Equity securities without readily determinable fair value $ 204,100,000