GOODWILL AND OTHER INTANGIBLE ASSETS (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Aug. 31, 2016	Apr. 30, 2016	Dec. 31, 2014
Goodwill	$ 5,694	$ 5,694
Deposit based intangible assets	1,860	$ 1,922
Amortization expense	62
Amortization expense year one	250
Amortization expense year two	250
Amortization expense year three	250
Amortization expense year four	250
Amortization expense year five	$ 250
PFC
Goodwill						$ 3,805
Deposit based intangible assets						$ 1,206
Eagle River
Goodwill			$ 1,839		$ 1,839
Deposit based intangible assets			$ 993
Niagara Bancorporation
Goodwill				$ 50
Deposit based intangible assets				$ 300