Goodwill and Other Intangible Assets - Additional Information (Detail)		9 Months Ended	12 Months Ended
	Mar. 18, 2016 USD ($) branch	Sep. 30, 2021 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Jul. 06, 2018 USD ($)	Oct. 03, 2014 USD ($)	Sep. 23, 2011 USD ($)
Finite-Lived Intangible Assets [Line Items]
Impairment charges		$ 0	$ 0	$ 0	$ 0
FNBB
Finite-Lived Intangible Assets [Line Items]
Additions to core deposit intangibles						$ 27,605,000
Bank of America
Finite-Lived Intangible Assets [Line Items]
Additions to core deposit intangibles	$ 2,046,000
Number of branches (in branches) | branch	3
North Valley Bancorp
Finite-Lived Intangible Assets [Line Items]
Additions to core deposit intangibles							$ 6,614,000
Citizens
Finite-Lived Intangible Assets [Line Items]
Additions to core deposit intangibles								$ 898,000