Loans and allowance for loan losses - Aging of recorded investment in past due loans and leases (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021	Dec. 31, 2020
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	$ 540,683	$ 526,457	$ 526,457
Total Loans		526,457
Total loans	540,683
Recorded Investment, 90 Days and Accruing		1,961
Recorded Investment, 90 Days and Accruing	1,714
Current
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	537,413	521,718
Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	3,270	4,739
30 to 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	1,160	1,987
60 to 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	396	791
Greater than 90 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	1,714	1,961
Consumer and other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	4,078		3,003
Construction and land development
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	40,546	49,149	49,149
Total Loans		49,149
Total loans	40,546
Construction and land development | Current
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	40,546	49,149
Construction and land development | Residential
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	8,437	6,805	6,805
Total Loans		6,805
Total loans	8,437
Construction and land development | Residential | Current
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	8,437	6,805
Construction and land development | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	32,109	42,344	42,344
Total Loans		42,344
Total loans	32,109
Construction and land development | Commercial | Current
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	32,109	42,344
Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	289,921	255,537	255,537
Total Loans		255,537
Total loans	289,921
Commercial real estate | Current
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	289,921	255,537
Commercial real estate | Owner occupied
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	122,067	113,108	113,108
Total Loans		113,108
Total loans	122,067
Commercial real estate | Owner occupied | Current
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	122,067	113,108
Commercial real estate | Non-owner occupied
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	155,981	129,786	129,786
Total Loans		129,786
Total loans	155,981
Commercial real estate | Non-owner occupied | Current
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	155,981	129,786
Commercial real estate | Multifamily
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	11,309	11,666	11,666
Total Loans		11,666
Total loans	11,309
Commercial real estate | Multifamily | Current
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	11,309	11,666
Commercial real estate | Farmland
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	564	977	977
Total Loans		977
Total loans	564
Commercial real estate | Farmland | Current
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	564	977
Consumer real estate secured by 1-4 family residential
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	92,525	92,372	92,372
Total Loans		92,372
Total loans	92,525
Consumer real estate secured by 1-4 family residential | Current
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	92,525	92,372
Consumer real estate secured by 1-4 family residential | Home equity lines
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	19,891	17,977	17,977
Total Loans		17,977
Total loans	19,891
Consumer real estate secured by 1-4 family residential | Home equity lines | Current
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	19,891	17,977
Consumer real estate secured by 1-4 family residential | First deed of trust
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	65,704	62,277	62,277
Total Loans		62,277
Total loans	65,704
Consumer real estate secured by 1-4 family residential | First deed of trust | Current
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	65,704	62,277
Consumer real estate secured by 1-4 family residential | Second deed of trust
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	6,930	12,118	12,118
Total Loans		12,118
Total loans	6,930
Consumer real estate secured by 1-4 family residential | Second deed of trust | Current
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	6,930	12,118
Commercial and industrial loans | Commercial and industrial loans (except those secured by real estate)
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	91,603	100,421	100,421
Total Loans		100,421
Total loans	91,603
Commercial and industrial loans | Commercial and industrial loans (except those secured by real estate) | Current
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	91,226	99,390
Commercial and industrial loans | Commercial and industrial loans (except those secured by real estate) | Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	377	1,031
Commercial and industrial loans | Commercial and industrial loans (except those secured by real estate) | 30 to 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	377	1,031
Commercial and industrial loans | Guaranteed student loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	22,010	25,975	$ 25,975
Total Loans		25,975
Total loans	22,010
Recorded Investment, 90 Days and Accruing		1,961
Recorded Investment, 90 Days and Accruing	1,714
Commercial and industrial loans | Guaranteed student loans | Current
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	19,117	22,267
Commercial and industrial loans | Guaranteed student loans | Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	2,893	3,708
Commercial and industrial loans | Guaranteed student loans | 30 to 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	783	956
Commercial and industrial loans | Guaranteed student loans | 60 to 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	396	791
Commercial and industrial loans | Guaranteed student loans | Greater than 90 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	1,714	1,961
Commercial and industrial loans | Consumer and other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	4,078	3,003
Total Loans		3,003
Total loans	4,078
Commercial and industrial loans | Consumer and other | Current
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	$ 4,078	$ 3,003