Actual regulatory capital position and minimum capital requirements (Details) $ in Thousands	Mar. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Total Capital To Risk Weighted Assets [Member]
Banking Regulation, Total Capital, Actual	$ 155,665	$ 152,789
Banking Regulation, Total Risk-Based Capital Ratio, Actual	0.1398	0.1408
Banking Regulation, Total Risk-Based Capital, Capital Adequacy, Minimum	$ 89,075	$ 86,832
Banking Regulation, Total Risk-Based Capital Ratio, Capital Adequacy, Minimum	0.080	0.080
[custom:TotalCapitalMinimumCapitalRequiredForCapitalAdequacyPlusRequiredCapitalConservationBufferAmount-0]	$ 116,911	$ 113,968
[custom:TotalCapitalMinimumCapitalRequiredForCapitalAdequacyPlusRequiredCapitalConservationBufferRatio-0]	10.50%	10.50%
Banking Regulation, Total Risk-Based Capital, Well Capitalized, Minimum	$ 111,344	$ 108,541
Banking Regulation, Total Risk-Based Capital Ratio, Well Capitalized, Minimum	0.100	0.100
Tier 1 Capital To Risk Weighted Assets [Member]
Banking Regulation, Total Capital, Actual	$ 142,567	$ 139,681
Banking Regulation, Total Risk-Based Capital Ratio, Actual	0.1280	0.1287
Banking Regulation, Total Risk-Based Capital, Capital Adequacy, Minimum	$ 66,806	$ 65,124
Banking Regulation, Total Risk-Based Capital Ratio, Capital Adequacy, Minimum	0.060	0.060
[custom:TotalCapitalMinimumCapitalRequiredForCapitalAdequacyPlusRequiredCapitalConservationBufferAmount-0]	$ 94,642	$ 92,259
[custom:TotalCapitalMinimumCapitalRequiredForCapitalAdequacyPlusRequiredCapitalConservationBufferRatio-0]	8.50%	8.50%
Banking Regulation, Total Risk-Based Capital, Well Capitalized, Minimum	$ 89,075	$ 86,832
Banking Regulation, Total Risk-Based Capital Ratio, Well Capitalized, Minimum	0.080	0.080
Common Equity Tier 1 Capital To Risk Weighted Assets [Member]
Banking Regulation, Total Capital, Actual	$ 142,567	$ 139,681
Banking Regulation, Total Risk-Based Capital Ratio, Actual	0.1280	0.1287
Banking Regulation, Total Risk-Based Capital, Capital Adequacy, Minimum	$ 50,105	$ 48,843
Banking Regulation, Total Risk-Based Capital Ratio, Capital Adequacy, Minimum	0.045	0.045
[custom:TotalCapitalMinimumCapitalRequiredForCapitalAdequacyPlusRequiredCapitalConservationBufferAmount-0]	$ 77,941	$ 75,978
[custom:TotalCapitalMinimumCapitalRequiredForCapitalAdequacyPlusRequiredCapitalConservationBufferRatio-0]	7.00%	7.00%
Banking Regulation, Total Risk-Based Capital, Well Capitalized, Minimum	$ 72,374	$ 70,551
Banking Regulation, Total Risk-Based Capital Ratio, Well Capitalized, Minimum	0.065	0.065
Tier 1 Capital To Average Assets [Member]
Banking Regulation, Total Capital, Actual	$ 142,567	$ 139,681
Banking Regulation, Total Risk-Based Capital Ratio, Actual	0.0966	0.0942
Banking Regulation, Total Risk-Based Capital, Capital Adequacy, Minimum	$ 59,010	$ 59,285
Banking Regulation, Total Risk-Based Capital Ratio, Capital Adequacy, Minimum	0.040	0.040
[custom:TotalCapitalMinimumCapitalRequiredForCapitalAdequacyPlusRequiredCapitalConservationBufferAmount-0]	$ 59,010	$ 59,285
[custom:TotalCapitalMinimumCapitalRequiredForCapitalAdequacyPlusRequiredCapitalConservationBufferRatio-0]	4.00%	4.00%
Banking Regulation, Total Risk-Based Capital, Well Capitalized, Minimum	$ 73,763	$ 74,106
Banking Regulation, Total Risk-Based Capital Ratio, Well Capitalized, Minimum	0.050	0.050