Allowance for Credit Losses - Loans - Residential and consumer portfolio (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Performing and non-performing outstanding balances of the residential and consumer portfolios
Total loans	$ 1,039,033		$ 1,039,033		$ 1,038,271
Current period gross charge-offs, Total	252	$ 30	416	$ 169
Residential mortgages
Performing and non-performing outstanding balances of the residential and consumer portfolios
Total loans	178,562		178,562		174,670
Consumer
Performing and non-performing outstanding balances of the residential and consumer portfolios
Total loans	12		12
Residential and Consumer
Performing and non-performing outstanding balances of the residential and consumer portfolios
2024/2023	11,244		11,244		28,481
2023/2022	28,471		28,471		32,050
2022/2021	29,149		29,149		70,954
2021/2020	68,248		68,248		47,312
2020/2019	45,756		45,756		8,303
Prior	49,303		49,303		40,956
Revolving Loans Amortized to Basis	50,830		50,830		48,501
Revolving Loans Converted to Term	266		266		888
Total loans	283,267		283,267		277,445
Current period gross charge-offs, 2024/2023					9
Current period gross charge-offs, 2023/2022			2		35
Current period gross charge-offs, 2022/2021			21		43
Current period gross charge-offs, 2021/2020			10		7
Current period gross charge-offs, 2020/2019			10		8
Current period gross charge-offs, Prior			81		227
Current period gross charge-offs, Total			124		329
Residential and Consumer | Residential mortgages
Performing and non-performing outstanding balances of the residential and consumer portfolios
2024/2023	5,781		5,781		14,576
2023/2022	15,757		15,757		11,620
2022/2021	10,696		10,696		61,172
2021/2020	59,661		59,661		44,049
2020/2019	42,840		42,840		7,092
Prior	43,827		43,827		36,161
Total loans	178,562		178,562		174,670
Current period gross charge-offs, Prior					54
Current period gross charge-offs, Total					54
Residential and Consumer | Consumer
Performing and non-performing outstanding balances of the residential and consumer portfolios
2024/2023	5,463		5,463		13,905
2023/2022	12,714		12,714		20,430
2022/2021	18,453		18,453		9,782
2021/2020	8,587		8,587		3,263
2020/2019	2,916		2,916		1,211
Prior	5,476		5,476		4,795
Revolving Loans Amortized to Basis	50,830		50,830		48,501
Revolving Loans Converted to Term	266		266		888
Total loans	104,705		104,705		102,775
Current period gross charge-offs, 2024/2023					9
Current period gross charge-offs, 2023/2022			2		35
Current period gross charge-offs, 2022/2021			21		43
Current period gross charge-offs, 2021/2020			10		7
Current period gross charge-offs, 2020/2019			10		8
Current period gross charge-offs, Prior			81		173
Current period gross charge-offs, Total	63	$ 30	124	$ 169	275
Performing | Residential and Consumer
Performing and non-performing outstanding balances of the residential and consumer portfolios
2024/2023	11,244		11,244		28,466
2023/2022	28,457		28,457		32,050
2022/2021	29,149		29,149		70,954
2021/2020	68,248		68,248		47,239
2020/2019	45,692		45,692		8,261
Prior	48,413		48,413		39,958
Revolving Loans Amortized to Basis	50,684		50,684		48,344
Revolving Loans Converted to Term	266		266		667
Total loans	282,153		282,153		275,939
Performing | Residential and Consumer | Residential mortgages
Performing and non-performing outstanding balances of the residential and consumer portfolios
2024/2023	5,781		5,781		14,576
2023/2022	15,757		15,757		11,620
2022/2021	10,696		10,696		61,172
2021/2020	59,661		59,661		44,049
2020/2019	42,840		42,840		7,092
Prior	43,432		43,432		35,443
Total loans	178,167		178,167		173,952
Performing | Residential and Consumer | Consumer
Performing and non-performing outstanding balances of the residential and consumer portfolios
2024/2023	5,463		5,463		13,890
2023/2022	12,700		12,700		20,430
2022/2021	18,453		18,453		9,782
2021/2020	8,587		8,587		3,190
2020/2019	2,852		2,852		1,169
Prior	4,981		4,981		4,515
Revolving Loans Amortized to Basis	50,684		50,684		48,344
Revolving Loans Converted to Term	266		266		667
Total loans	103,986		103,986		101,987
Non-performing | Residential and Consumer
Performing and non-performing outstanding balances of the residential and consumer portfolios
2024/2023					15
2023/2022	14		14
2021/2020					73
2020/2019	64		64		42
Prior	890		890		998
Revolving Loans Amortized to Basis	146		146		157
Revolving Loans Converted to Term					221
Total loans	1,114		1,114		1,506
Non-performing | Residential and Consumer | Residential mortgages
Performing and non-performing outstanding balances of the residential and consumer portfolios
Prior	395		395		718
Total loans	395		395		718
Non-performing | Residential and Consumer | Consumer
Performing and non-performing outstanding balances of the residential and consumer portfolios
2024/2023					15
2023/2022	14		14
2021/2020					73
2020/2019	64		64		42
Prior	495		495		280
Revolving Loans Amortized to Basis	146		146		157
Revolving Loans Converted to Term					221
Total loans	$ 719		$ 719		$ 788