Investment Securities - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2024 USD ($) assetBackedSecurity security corporateNote	Mar. 31, 2023 USD ($) assetBackedSecurity corporateNote	Dec. 31, 2023 USD ($) security
Debt Securities, Available-for-sale [Line Items]
Proceeds from sales of investment securities available for sale	$ 21,970,000	$ 0
Number of available-for-sale investment securities, unrealized loss position, less than twelve month category | security	38
Number of available-for-sale investment securities, unrealized loss position, twelve month or more category | security	102
Number of asset-backed securities with deterioration in future estimated cash flows | assetBackedSecurity	1	4
Number of corporate notes with deterioration in future estimated cash flows | corporateNote	19	6
Number of available-for-sale investment securities, unrealized loss position | security	140		119
Debt securities, available for sale	$ 2,571,139,000		$ 2,376,860,000
Debt securities, held-to-maturity, allowance for credit loss, excluding accrued interest	0		0
Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Debt securities, available for sale	58,234,000		92,629,000
Debt securities, held-to-maturity, allowance for credit loss, excluding accrued interest	0		0
Asset Pledged as Collateral
Debt Securities, Available-for-sale [Line Items]
Debt securities, available for sale	1,300,000,000		1,200,000,000
Debt securities	$ 391,400,000		$ 398,400,000