LOANS (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Loans
Total loans	$ 811,078,000	$ 781,857,000
Acquired portfolio
Balance at the beginning of period	1,457,000
Acquisition		2,091,000
Accretion		(525,000)
Reclassification from nonaccretable difference		(109,000)
Balance at the end of period		1,457,000
PFC
Acquired portfolio
Loans acquired - contractual payments	67,139,000
Nonaccretable difference	(2,234,000)
Expected cash flows	64,905,000
Accretable yield	(2,844,000)
Carrying balance at acquisition date	62,061,000
Balance at the beginning of period	924,000	1,768,000
Accretion	(1,102,000)	(750,000)
Reclassification from nonaccretable difference	327,000	(94,000)
Balance at the end of period	149,000	924,000	$ 1,768,000
Eagle River
Acquired portfolio
Loans acquired - contractual payments	84,138,000
Nonaccretable difference	(1,172,000)
Expected cash flows	82,966,000
Accretable yield	(2,091,000)
Carrying balance at acquisition date	80,875,000
Balance at the beginning of period	1,457,000
Accretion	(688,000)
Reclassification from nonaccretable difference	52,000
Balance at the end of period	821,000	1,457,000
Niagara Bancorporation
Acquired portfolio
Loans acquired - contractual payments	32,660,000
Nonaccretable difference	(265,000)
Expected cash flows	32,395,000
Accretable yield	(688,000)
Carrying balance at acquisition date	31,707,000
Balance at the beginning of period	557,000
Acquisition		688,000
Accretion	(244,000)	(95,000)
Reclassification from nonaccretable difference	6,000	(36,000)
Balance at the end of period	319,000	557,000
Commercial real estate
Loans
Total loans	406,742,000	389,420,000
Commercial, financial, and agricultural
Loans
Total loans	156,951,000	142,648,000
Commercial construction
Loans
Total loans	9,243,000	11,505,000
One to four family residential real estate
Loans
Total loans	209,890,000	205,945,000
Consumer
Loans
Total loans	17,434,000	20,113,000
Consumer construction
Loans
Total loans	10,818,000	12,226,000
Acquired Impaired
Acquired portfolio
Accretion	(550,000)	(96,000)	(578,000)
Acquired Impaired | PFC
Acquired portfolio
Loans acquired - contractual payments	13,290,000
Nonaccretable difference	(2,234,000)
Expected cash flows	11,056,000
Accretable yield	(744,000)
Carrying balance at acquisition date	10,312,000
Balance at the beginning of period	282,000	426,000
Accretion	(460,000)	(50,000)
Reclassification from nonaccretable difference	327,000	(94,000)
Balance at the end of period	149,000	282,000	426,000
Acquired Impaired | Eagle River
Acquired portfolio
Loans acquired - contractual payments	3,401,000
Nonaccretable difference	(1,172,000)
Expected cash flows	2,229,000
Accretable yield	(391,000)
Carrying balance at acquisition date	1,838,000
Balance at the beginning of period	236,000
Acquisition		391,000
Accretion	(70,000)	(46,000)
Reclassification from nonaccretable difference	52,000	(109,000)
Balance at the end of period	218,000	236,000
Acquired Impaired | Niagara Bancorporation
Acquired portfolio
Loans acquired - contractual payments	2,105,000
Nonaccretable difference	(265,000)
Expected cash flows	1,840,000
Accretable yield	(88,000)
Carrying balance at acquisition date	1,752,000
Balance at the beginning of period	52,000
Acquisition		88,000
Accretion	(20,000)
Reclassification from nonaccretable difference	6,000	(36,000)
Balance at the end of period	38,000	52,000
Acquired Non-impaired | PFC
Acquired portfolio
Loans acquired - contractual payments	53,849,000
Expected cash flows	53,849,000
Accretable yield	(2,100,000)
Carrying balance at acquisition date	51,749,000
Balance at the beginning of period	642,000	1,342,000
Accretion	(642,000)	(700,000)
Balance at the end of period		642,000	$ 1,342,000
Acquired Non-impaired | Eagle River
Acquired portfolio
Loans acquired - contractual payments	80,737,000
Expected cash flows	80,737,000
Accretable yield	(1,700,000)
Carrying balance at acquisition date	79,037,000
Balance at the beginning of period	1,221,000
Acquisition		1,700,000
Accretion	(618,000)	(479,000)
Balance at the end of period	603,000	1,221,000
Acquired Non-impaired | Niagara Bancorporation
Acquired portfolio
Loans acquired - contractual payments	30,555,000
Expected cash flows	30,555,000
Accretable yield	(600,000)
Carrying balance at acquisition date	29,955,000
Balance at the beginning of period	505,000
Acquisition		600,000
Accretion	(224,000)	(95,000)
Balance at the end of period	$ 281,000	$ 505,000