INCOME TAXES (Details) - USD ($)		12 Months Ended
	Dec. 22, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current:
Federal		$ 4,603,000	$ 1,732,000	$ 2,594,000
State		395,000	124,000	417,000
Total current		4,998,000	1,856,000	3,011,000
Deferred expense/(benefit):
Federal		(1,126,000)	2,253,000	942,000
State		(438,000)	345,000	382,000
Remeasurement of deferred tax assets	$ 2,900,000	0	(445,000)	2,927,000
Total deferred		(1,564,000)	2,153,000	4,251,000
Income tax expense		$ 3,434,000	$ 4,009,000	$ 7,262,000
Reconciliation of income tax expense [Abstract]
Statutory federal tax rate		21.00%	21.00%	34.00%
Tax computed at statutory rate		$ 3,999,000	$ 4,963,000	$ 5,006,000
Tax-exempt income		(424,000)	(430,000)	(663,000)
831(b) premium adjustment		(189,000)	(167,000)	(269,000)
Dividend exclusion		(7,000)	(7,000)	(8,000)
State taxes, net of Federal impact		(86,000)	262,000	201,000
Nondeductible interest expense		9,000	7,000	8,000
Remeasurement of deferred tax assets		0	(445,000)	2,927,000
Other items, net		132,000	(174,000)	60,000
Income tax expense		$ 3,434,000	$ 4,009,000	$ 7,262,000
Effective tax rate		18.00%	17.00%	49.40%
Deferred tax assets:
Allowance for loan losses		$ 6,046,000	$ 4,834,000
Accrual for employee benefit plans		92,000	136,000
Depreciation			(93,000)
Depreciation		379,000
Deferred compensation and directors' fees		765,000	634,000
Operating lease liabilities		2,050,000
Purchase accounting adjustment – loans		1,000	7,000
Purchase accounting adjustment – fixed assets		149,000	149,000
Gain on deemed sale of securities		71,000	339,000
Net unrealized losses on securities available for sale		0	1,590,000
Accounting for defined benefit pension and other benefit plans		2,448,000	2,315,000
Nonaccrued interest		695,000	625,000
Accrued expense		179,000	200,000
Other items, net		38,000	153,000
Total gross deferred tax assets		12,913,000	10,889,000
Deferred tax liabilities:
Deferred loan fees and costs		592,000	640,000
Prepaid pension		3,189,000	3,141,000
Net unrealized gains on securities available for sale		468,000	0
Discount accretion		24,000	137,000
Core deposit intangible		1,213,000	1,101,000
REIT dividend		922,000	1,048,000
Operating lease right-of-use assets		2,050,000
Other		103,000	109,000
Total gross deferred tax liabilities		8,561,000	6,176,000
Net deferred tax asset		4,352,000	4,713,000
Unrecognized tax benefits		0	0	$ 0
Accrued interest or penalties related to uncertain tax positions		$ 0	$ 0	$ 0