Short-term borrowings (Details 2) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Assets Sold Under Agreements To Repurchase [Line Items]
Total borrowings	$ 2,521	$ 77,050
Repurchase agreement
Assets Sold Under Agreements To Repurchase [Line Items]
Total borrowings	2,171	1,700
Repurchase agreement | U.S. Treasury and U.S. government sponsored entities
Assets Sold Under Agreements To Repurchase [Line Items]
Total borrowings	42	55
Repurchase agreement | State and political subdivisions
Assets Sold Under Agreements To Repurchase [Line Items]
Total borrowings	1,407	627
Repurchase agreement | Mortgage-backed securities - residential
Assets Sold Under Agreements To Repurchase [Line Items]
Total borrowings	568	948
Repurchase agreement | Collateralized mortgage obligations
Assets Sold Under Agreements To Repurchase [Line Items]
Total borrowings	$ 154	$ 70