Securities - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Investment Holdings [Line Items]
Proceeds from sales of available for sale securities	$ 0	$ 0	$ 4,402,000
Gross gains			9,000
Gross losses			0
Securities, carrying value	1,570,000,000	1,340,000,000
Equity securities, at fair value	17,697,000	17,283,000
Proceeds from sales of equity securities	0	0	0
Loss on equity securities	$ 110,000	$ (1,302,000)	$ (285,000)
Redemption of funds, notice period	60 days
Unfunded commitments	$ 0
Fair value of securities	9,900,000
Community Reinvestment Funds
Investment Holdings [Line Items]
Equity securities, at fair value	7,800,000
Other Financial Institutions
Investment Holdings [Line Items]
Unfunded commitments	$ 0