Income Taxes, Deferred Tax Assets and Deferred Tax Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets [Abstract]
Allowance for loan losses	$ 4,838	$ 3,901
Deferred compensation	101	108
Retirement compensation	1,456	1,378
Stock option compensation	256	181
Postretirement benefits	871	576
Current state franchise taxes	467	457
Non-accrual interest	484	11
Sale-leaseback	51	75
Lease liability	1,900	2,212
Other	252	160
Deferred tax assets	10,676	9,059
Deferred tax liabilities [Abstract]
Fixed assets depreciation	1,357	1,455
FHLB dividends	184	187
Tax credit - loss on pass-through	499	210
Deferred loan costs	823	780
Mortgage servicing rights	143	164
Investment securities unrealized gain	2,903	630
Right of Use Asset	1,748	2,058
Other	89	94
Total deferred tax liabilities	7,746	5,578
Net deferred tax assets (see Note 7)	$ 2,930	$ 3,481