Income taxes - Components of Net Deferred Tax Asset (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Deferred tax assets:
Allowance for loan losses	$ 4,789	$ 5,916
Lease liability	2,397	1,787
Defined benefit plan	1,635	1,798
Deferred compensation	694	860
Deferred loan fees and costs		59
Investment securities available for sale	11,270	14,266
Other	339	196
Total	21,124	24,882
Deferred tax liabilities:
Lease right-of-use assets	2,313	1,718
Premises and equipment, net	2,109	1,692
Merger related accounting	474	472
Deferred loan costs	92
Accrued compensation	1,912	1,872
Other	454	389
Total	7,354	6,143
Net deferred tax asset	$ 13,770	$ 18,739