Investment Securities - Additional Information (Details)	3 Months Ended			9 Months Ended
	Sep. 30, 2023 USD ($) position	Mar. 31, 2023 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2023 USD ($) position	Sep. 30, 2022 USD ($)	Dec. 31, 2022 USD ($) position
Investments, Debt and Equity Securities [Abstract]
Equity securities	$ 63,191,000			$ 63,191,000		$ 48,731,000
Trading debt securities	3,441,000			3,441,000		13,438,000
Debt securities, trading, realized gain	45,000			673,000
Debt securities, trading realized gain (loss)			$ 290,000		$ (1,200,000)
Accrued interest on investments available for sale	$ 5,200,000			$ 5,200,000		$ 5,600,000
Number of security positions in the debt securities available for sale portfolio in an unrealized loss position | position	720			720		730
Fair value of debt securities available for sale pledged as collateral	$ 803,000,000			$ 803,000,000
Weighted-average remaining expected life of residential mortgage-backed securities available for sale, years				7 years 10 months 2 days
Provision for credit losses		$ 5,000,000		$ 5,000,000
Impairment loss	0		$ 0	0	$ 0
Accrued interest on securities held to maturity	$ 13,000,000			$ 13,000,000		$ 13,500,000
Number of security positions in the securities held to maturity portfolio in an unrealized loss position | position	842			842		802
Fair value of investments held to maturity pledged as collateral	$ 2,400,000,000			$ 2,400,000,000
Weighted-average remaining expected life of residential mortgage-backed securities held to maturity, years				9 years 10 months 2 days