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Loans and Allowance for Credit Losses on Loans - CARES Act Narrative (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2021 USD ($) loan branch	Dec. 31, 2020 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans at amortized cost	$ 2,317,019	$ 2,088,556
SBA PPP
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans | loan	871
SBA PPP | American River Bank (ARB)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans funded during period | branch	31
Loans at amortized cost	$ 9,600
SBA PPP Round Two
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans funded during period | loan	790
Commercial loans | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans at amortized cost	$ 377,965	498,408
Commercial loans | Commercial and industrial | SBA PPP
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans at amortized cost	164,800	291,600
Financing receivable, unamortized loan fee	4,200	$ 5,400
Commercial loans | Commercial and industrial | SBA PPP Round Two
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans at amortized cost	$ 123,900

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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
-Topic 326
-SubTopic 20
-Section 50
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