Income Taxes - Effective Tax Rates Differed from Statutory Federal Income Tax Rate (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Income taxes computed at the statutory federal tax rate	$ 9,878	$ 9,988	$ 7,798
Add (subtract) tax effect of:
Nontaxable interest income, net of nondeductible interest expense	(1,666)	(1,315)	(1,293)
Low income housing tax credit	(679)	(1,402)	(1,186)
Cash surrender value of BOLI	(207)	(252)	(205)
Other	282	(2)	(174)
Income tax expense	$ 7,608	$ 7,017	$ 4,940