Loans - Nonaccrual TDRs and the related specific valuation allowance by portfolio segment (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($) loan	Dec. 31, 2020 USD ($) loan
Information concerning Troubled Debt Restructurings
Recorded Investment	$ 6,485	$ 7,491
Number of Loans	28	34
Specific Valuation Allowance
Information concerning Troubled Debt Restructurings
Recorded Investment	$ 11	$ 17
Number of Loans	3	2
Performing Financing Receivable
Information concerning Troubled Debt Restructurings
Recorded Investment	$ 5,734	$ 6,550
Number of Loans	23	27
Nonperforming Financial Instruments
Information concerning Troubled Debt Restructurings
Recorded Investment	$ 751	$ 941
Number of Loans	5	7
Commercial real estate
Information concerning Troubled Debt Restructurings
Recorded Investment	$ 4,701	$ 5,387
Commercial real estate | Specific Valuation Allowance
Information concerning Troubled Debt Restructurings
Recorded Investment	4	9
Commercial real estate | Performing Financing Receivable
Information concerning Troubled Debt Restructurings
Recorded Investment	4,415	5,084
Commercial real estate | Nonperforming Financial Instruments
Information concerning Troubled Debt Restructurings
Recorded Investment	286	303
Consumer real estate
Information concerning Troubled Debt Restructurings
Recorded Investment	1,765	2,077
Consumer real estate | Specific Valuation Allowance
Information concerning Troubled Debt Restructurings
Recorded Investment	7	8
Consumer real estate | Performing Financing Receivable
Information concerning Troubled Debt Restructurings
Recorded Investment	1,319	1,466
Consumer real estate | Nonperforming Financial Instruments
Information concerning Troubled Debt Restructurings
Recorded Investment	446	611
Owner occupied | Commercial real estate
Information concerning Troubled Debt Restructurings
Recorded Investment	3,243	3,396
Owner occupied | Commercial real estate | Specific Valuation Allowance
Information concerning Troubled Debt Restructurings
Recorded Investment	4	9
Owner occupied | Commercial real estate | Performing Financing Receivable
Information concerning Troubled Debt Restructurings
Recorded Investment	3,243	3,396
Non-owner occupied | Commercial real estate
Information concerning Troubled Debt Restructurings
Recorded Investment	1,458	$ 1,991
Number of Loans | loan		1
Non-owner occupied | Commercial real estate | Performing Financing Receivable
Information concerning Troubled Debt Restructurings
Recorded Investment	1,172	$ 1,688
Non-owner occupied | Commercial real estate | Nonperforming Financial Instruments
Information concerning Troubled Debt Restructurings
Recorded Investment	286	303
First deed of trust | Consumer real estate
Information concerning Troubled Debt Restructurings
Recorded Investment	$ 1,666	1,460
Number of Loans | loan	1
First deed of trust | Consumer real estate | Specific Valuation Allowance
Information concerning Troubled Debt Restructurings
Recorded Investment	$ 7	8
First deed of trust | Consumer real estate | Performing Financing Receivable
Information concerning Troubled Debt Restructurings
Recorded Investment	1,279	910
First deed of trust | Consumer real estate | Nonperforming Financial Instruments
Information concerning Troubled Debt Restructurings
Recorded Investment	387	550
Second deed of trust | Consumer real estate
Information concerning Troubled Debt Restructurings
Recorded Investment	99	617
Second deed of trust | Consumer real estate | Performing Financing Receivable
Information concerning Troubled Debt Restructurings
Recorded Investment	40	556
Second deed of trust | Consumer real estate | Nonperforming Financial Instruments
Information concerning Troubled Debt Restructurings
Recorded Investment	59	61
Commercial and industrial loans (except those secured by real estate) | Commercial and industrial loans
Information concerning Troubled Debt Restructurings
Recorded Investment	19	27
Commercial and industrial loans (except those secured by real estate) | Commercial and industrial loans | Nonperforming Financial Instruments
Information concerning Troubled Debt Restructurings
Recorded Investment	$ 19	$ 27