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Loans and Allowance for Credit Losses - Commercial and Industrial Loans Narrative (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($) loan	Dec. 31, 2020 USD ($)	Jun. 30, 2021 USD ($) loan
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans, at amortized cost	$ 2,255,645	$ 2,088,556
Commercial | Commercial and industrial
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans, at amortized cost	301,602	498,408
Small Business Administration Paycheck Protection Program | Commercial | Commercial and industrial
Financing Receivable, Allowance for Credit Loss [Line Items]
Number of loans | loan			2,876
Loans, at amortized cost	111,200	291,600	$ 444,100
Unrecognized loan fees, net of costs	2,500	5,400
Recognized loan fees, net of cost	$ 8,300	$ 3,800
Small Business Administration Paycheck Protection Program | Commercial | Commercial and industrial | American River Bank ARB
Financing Receivable, Allowance for Credit Loss [Line Items]
Number of loans | loan	13
Loans, at amortized cost	$ 2,800

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Number Of Loans

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Amount excluding accrued interest, before allowance for credit loss, of financing receivable.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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Amount of unamortized loan commitment, origination, and other fees (costs) on financing receivable. Excludes financing receivable covered under loss sharing agreement.

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