Income Taxes, Deferred Tax Assets and Deferred Tax Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets [Abstract]
Allowance for loan losses	$ 3,901	$ 4,027
Deferred compensation	108	116
Retirement compensation	1,378	1,313
Stock option compensation	181	127
Postretirement benefits	576	472
Current state franchise taxes	457	470
Non-accrual interest	11	118
Low income housing tax credit partnership	0	128
Sale-leaseback	75	100
Lease liability	2,212	0
Investment securities unrealized loss	0	1,560
Other	160	282
Deferred tax assets	9,059	8,713
Deferred tax liabilities [Abstract]
Fixed assets depreciation	1,455	1,478
FHLB dividends	187	187
Tax credit - loss on pass-through	210	0
Deferred loan costs	780	806
Mortgage servicing rights	164	142
Investment securities unrealized gain	630	0
Right of Use Asset	2,058	0
Other	94	84
Total deferred tax liabilities	5,578	2,697
Net deferred tax assets (see Note 7)	$ 3,481	$ 6,016