Fair value estimates - Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - Recurring Basis - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, Fair Value Estimate	$ 514,032	$ 517,461
U.S. Treasury securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, Fair Value Estimate	236,458	191,574
U.S. Government-sponsored enterprises state and municipals
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, Fair Value Estimate	23,165	33,778
State and Municipals, Taxable
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, Fair Value Estimate	59,972	68,978
State and Municipals, Tax-exempt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, Fair Value Estimate	89,272	98,250
Corporate Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, Fair Value Estimate	3,710	2,918
Mortgage-backed Securities, U.S. Government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, Fair Value Estimate	1,276	1,843
Mortgage-backed Securities, U.S. Government-sponsored enterprises
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, Fair Value Estimate	100,058	119,980
Equity Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, Fair Value Estimate	121	140
Loan held for sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, Fair Value Estimate	681	408
Interest rate floor - other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, Fair Value Estimate	97	844
Interest rate swap-other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, Fair Value Estimate	14,720	9,026
Interest rate swap-other liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities measured at fair value	(13,982)	(8,811)
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, Fair Value Estimate	236,579	191,714
Level 1 | U.S. Treasury securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, Fair Value Estimate	236,458	191,574
Level 1 | Equity Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, Fair Value Estimate	121	140
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, Fair Value Estimate	277,453	325,747
Level 2 | U.S. Government-sponsored enterprises state and municipals
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, Fair Value Estimate	23,165	33,778
Level 2 | State and Municipals, Taxable
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, Fair Value Estimate	59,972	68,978
Level 2 | State and Municipals, Tax-exempt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, Fair Value Estimate	89,272	98,250
Level 2 | Corporate Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, Fair Value Estimate	3,710	2,918
Level 2 | Mortgage-backed Securities, U.S. Government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, Fair Value Estimate	1,276	1,843
Level 2 | Mortgage-backed Securities, U.S. Government-sponsored enterprises
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, Fair Value Estimate	100,058	119,980
Level 2 | Loan held for sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, Fair Value Estimate	681	408
Level 2 | Interest rate floor - other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, Fair Value Estimate	97	844
Level 2 | Interest rate swap-other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, Fair Value Estimate	14,720	9,026
Level 2 | Interest rate swap-other liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Liabilities measured at fair value	$ (13,982)	$ (8,811)