Loans and allowance for loan losses - Impaired loans (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
With no related allowance recorded
Recorded Investment	$ 290	$ 291
Unpaid Principle Balance	290	291
With an allowance recorded
Recorded Investment	79
Unpaid Principle Balance	79
Related Allowance	15
Total
Recorded Investment	369	291
Unpaid Principle Balance	369	291
Related Allowance	15
Consumer real estate
With no related allowance recorded
Recorded Investment	266	265
Unpaid Principle Balance	266	265
Total
Recorded Investment	266	265
Unpaid Principle Balance	266	265
Consumer real estate | Home equity lines
With no related allowance recorded
Recorded Investment	25
Unpaid Principle Balance	25
Total
Recorded Investment	25
Unpaid Principle Balance	25
Consumer Real Estate Secured By 1-4 Family Residential | First deed of trust
With no related allowance recorded
Recorded Investment	156	160
Unpaid Principle Balance	156	160
Total
Recorded Investment	156	160
Unpaid Principle Balance	156	160
Consumer Real Estate Secured By 1-4 Family Residential | Second deed of trust
With no related allowance recorded
Recorded Investment	85	105
Unpaid Principle Balance	85	105
Total
Recorded Investment	85	105
Unpaid Principle Balance	85	105
Commercial and industrial loans | Commercial and industrial loans (except those secured by real estate)
With no related allowance recorded
Recorded Investment	24	26
Unpaid Principle Balance	24	26
With an allowance recorded
Recorded Investment	79
Unpaid Principle Balance	79
Related Allowance	15
Total
Recorded Investment	103	26
Unpaid Principle Balance	103	$ 26
Related Allowance	$ 15