Loans - Allowance for loan losses (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	$ 3,970,000	$ 3,186,000
Provision for (Recovery of) Loan Losses	(500,000)	950,000
Charge-offs	(165,000)	(292,000)
Recoveries	118,000	126,000
Ending Balance	3,423,000	3,970,000
Consumer and other
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	190,000
Ending Balance	451,000	190,000
Construction and land development
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	499,000	185,000
Provision for (Recovery of) Loan Losses	(213,000)	289,000
Recoveries		25,000
Ending Balance	286,000	499,000
Construction and land development | Residential
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	214,000	48,000
Provision for (Recovery of) Loan Losses	(157,000)	141,000
Recoveries		25,000
Ending Balance	57,000	214,000
Construction and land development | Commercial
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	285,000	137,000
Provision for (Recovery of) Loan Losses	(56,000)	148,000
Ending Balance	229,000	285,000
Commercial real estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	2,517,000	1,589,000
Provision for (Recovery of) Loan Losses	(578,000)	928,000
Recoveries	14,000
Ending Balance	1,953,000	2,517,000
Commercial real estate | Owner occupied
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	1,047,000	671,000
Provision for (Recovery of) Loan Losses	(214,000)	376,000
Ending Balance	833,000	1,047,000
Commercial real estate | Non-owner occupied
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	1,421,000	831,000
Provision for (Recovery of) Loan Losses	(352,000)	590,000
Recoveries	14,000
Ending Balance	1,083,000	1,421,000
Commercial real estate | Multifamily
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	47,000	85,000
Provision for (Recovery of) Loan Losses	(12,000)	(38,000)
Ending Balance	35,000	47,000
Commercial real estate | Farmland
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	2,000	2,000
Ending Balance	2,000	2,000
Consumer real estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	269,000	678,000
Provision for (Recovery of) Loan Losses	(76,000)	(392,000)
Charge-offs	(84,000)	(85,000)
Recoveries	73,000	68,000
Ending Balance	182,000	269,000
Consumer real estate | Home equity lines
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	24,000	271,000
Provision for (Recovery of) Loan Losses	(23,000)	(247,000)
Recoveries	11,000
Ending Balance	12,000	24,000
Consumer real estate | First deed of trust
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	166,000	343,000
Provision for (Recovery of) Loan Losses	(54,000)	(190,000)
Recoveries	11,000	13,000
Ending Balance	123,000	166,000
Consumer real estate | Second deed of trust
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	79,000	64,000
Provision for (Recovery of) Loan Losses	1,000	45,000
Charge-offs	(84,000)	(85,000)
Recoveries	51,000	55,000
Ending Balance	47,000	79,000
Commercial and industrial loans | Commercial and industrial loans (except those secured by real estate)
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	408,000	572,000
Provision for (Recovery of) Loan Losses	47,000	(58,000)
Charge-offs		(135,000)
Recoveries	31,000	29,000
Ending Balance	486,000	408,000
Commercial and industrial loans | Guaranteed student loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	87,000	108,000
Provision for (Recovery of) Loan Losses	13,000	27,000
Charge-offs	(35,000)	(48,000)
Ending Balance	65,000	87,000
Commercial and industrial loans | Consumer and other
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	36,000	30,000
Provision for (Recovery of) Loan Losses	39,000	26,000
Charge-offs	(46,000)	(24,000)
Recoveries		4,000
Ending Balance	29,000	36,000
Commercial and industrial loans | Unallocated
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	154,000	24,000
Provision for (Recovery of) Loan Losses	268,000	130,000
Ending Balance	$ 422,000	$ 154,000