Loans - Impaired Loan (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Recorded Investment
Impaired loan, with no related allowance, recorded investment	$ 1,203	$ 1,099
Impaired loan, with related allowance, recorded investment	989	235
Impaired loan, total, recorded investment	2,192	1,334
Unpaid Principal Balance
Impaired loan, with no related allowance, unpaid principal balance	1,202	1,096
Impaired loan, with related allowance, unpaid principal balance	984	231
Impaired loan, total, unpaid principal balance	2,186	1,327
Impaired loan, total, related allowance	230	64
Average Recorded Investment
Impaired loan, with no related allowance, average recorded investment	1,137	1,571
Impaired loan, with related allowance, average recorded investment	416	863
Impaired loan, total, average recorded investment	1,553	2,434
Interest Income Recognized
Impaired loan, with no related allowance, interest income recognized	88	89
Impaired loan, with related allowance, interest income recognized	57	50
Impaired loan, total, interest income recognized	145	139
Commercial
Recorded Investment
Impaired loan, with no related allowance, recorded investment	49	28
Impaired loan, with related allowance, recorded investment	735	62
Impaired loan, total, recorded investment	784	90
Unpaid Principal Balance
Impaired loan, with no related allowance, unpaid principal balance	49	28
Impaired loan, with related allowance, unpaid principal balance	730	58
Impaired loan, total, unpaid principal balance	779	86
Impaired loan, total, related allowance	204	55
Average Recorded Investment
Impaired loan, with no related allowance, average recorded investment	16	44
Impaired loan, with related allowance, average recorded investment	191	354
Impaired loan, total, average recorded investment	207	398
Interest Income Recognized
Impaired loan, with no related allowance, interest income recognized	5	14
Impaired loan, with related allowance, interest income recognized	41	40
Impaired loan, total, interest income recognized	46	54
Commercial Real Estate | Construction and land development
Recorded Investment
Impaired loan, with no related allowance, recorded investment	0	0
Impaired loan, with related allowance, recorded investment	0	0
Impaired loan, total, recorded investment	0	0
Unpaid Principal Balance
Impaired loan, with no related allowance, unpaid principal balance	0	0
Impaired loan, with related allowance, unpaid principal balance	0	0
Impaired loan, total, unpaid principal balance	0	0
Impaired loan, total, related allowance	0	0
Average Recorded Investment
Impaired loan, with no related allowance, average recorded investment	0	0
Impaired loan, with related allowance, average recorded investment	0	21
Impaired loan, total, average recorded investment	0	21
Interest Income Recognized
Impaired loan, with no related allowance, interest income recognized	0	0
Impaired loan, with related allowance, interest income recognized	0	0
Impaired loan, total, interest income recognized	0	0
Commercial Real Estate | Real estate
Recorded Investment
Impaired loan, with no related allowance, recorded investment	502	376
Impaired loan, with related allowance, recorded investment	0	0
Impaired loan, total, recorded investment	502	376
Unpaid Principal Balance
Impaired loan, with no related allowance, unpaid principal balance	500	373
Impaired loan, with related allowance, unpaid principal balance	0	0
Impaired loan, total, unpaid principal balance	500	373
Impaired loan, total, related allowance	0	0
Average Recorded Investment
Impaired loan, with no related allowance, average recorded investment	424	542
Impaired loan, with related allowance, average recorded investment	0	18
Impaired loan, total, average recorded investment	424	560
Interest Income Recognized
Impaired loan, with no related allowance, interest income recognized	39	36
Impaired loan, with related allowance, interest income recognized	0	0
Impaired loan, total, interest income recognized	39	36
Residential Real Estate | Real estate
Recorded Investment
Impaired loan, with no related allowance, recorded investment	611	646
Impaired loan, with related allowance, recorded investment	254	173
Impaired loan, total, recorded investment	865	819
Unpaid Principal Balance
Impaired loan, with no related allowance, unpaid principal balance	612	646
Impaired loan, with related allowance, unpaid principal balance	254	173
Impaired loan, total, unpaid principal balance	866	819
Impaired loan, total, related allowance	26	9
Average Recorded Investment
Impaired loan, with no related allowance, average recorded investment	652	875
Impaired loan, with related allowance, average recorded investment	225	342
Impaired loan, total, average recorded investment	877	1,217
Interest Income Recognized
Impaired loan, with no related allowance, interest income recognized	38	29
Impaired loan, with related allowance, interest income recognized	16	9
Impaired loan, total, interest income recognized	54	38
Residential Real Estate | Home equity
Recorded Investment
Impaired loan, with no related allowance, recorded investment	41	49
Impaired loan, with related allowance, recorded investment	0	0
Impaired loan, total, recorded investment	41	49
Unpaid Principal Balance
Impaired loan, with no related allowance, unpaid principal balance	41	49
Impaired loan, with related allowance, unpaid principal balance	0	0
Impaired loan, total, unpaid principal balance	41	49
Impaired loan, total, related allowance	0	0
Average Recorded Investment
Impaired loan, with no related allowance, average recorded investment	45	108
Impaired loan, with related allowance, average recorded investment	0	128
Impaired loan, total, average recorded investment	45	236
Interest Income Recognized
Impaired loan, with no related allowance, interest income recognized	6	10
Impaired loan, with related allowance, interest income recognized	0	1
Impaired loan, total, interest income recognized	6	11
Consumer
Recorded Investment
Impaired loan, with no related allowance, recorded investment	0	0
Impaired loan, with related allowance, recorded investment	0	0
Impaired loan, total, recorded investment	0	0
Unpaid Principal Balance
Impaired loan, with no related allowance, unpaid principal balance	0	0
Impaired loan, with related allowance, unpaid principal balance	0	0
Impaired loan, total, unpaid principal balance	0	0
Impaired loan, total, related allowance	0	0
Average Recorded Investment
Impaired loan, with no related allowance, average recorded investment	0	2
Impaired loan, with related allowance, average recorded investment	0	0
Impaired loan, total, average recorded investment	0	2
Interest Income Recognized
Impaired loan, with no related allowance, interest income recognized	0	0
Impaired loan, with related allowance, interest income recognized	0	0
Impaired loan, total, interest income recognized	$ 0	$ 0