Investment Securities - Additional Information (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2024 USD ($) Security Securities	Sep. 30, 2023 USD ($)	Sep. 30, 2024 USD ($) Security Securities	Sep. 30, 2023 USD ($)	Dec. 31, 2023 USD ($) Security Securities
Debt Securities, Available-for-Sale [Line Items]
Allowance for credit losses on available for sale debt securities	$ 0		$ 0		$ 0
Number of debt securities with unrealized losses | Securities	175		175		164
Held to maturity debt securities | Security	11		11		12
Proceeds from sales	$ 0	$ 0	$ 1,691,000	$ 1,847,000
Accrued interest receivable on available for sale debt securities	710,000		710,000
Accrued interest receivable on held-to-maturity debt securities	180,000		180,000
Tax (provision) benefit	(1,000)	$ 498,000	(1,000)	498,000
Pledged debt securities with a carrying value	61,400,000		61,400,000		$ 65,900,000
Investment in subordinated notes	$ 149,315,000		149,315,000		$ 115,490,000
Loss incurred on sale of investment			$ 4,000	$ (2,370,000)