GOODWILL AND OTHER INTANGIBLE ASSETS - Changes in carrying amounts of goodwill and other intangibles (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
GOODWILL AND OTHER INTANGIBLE ASSETS
Goodwill, Beginning Balance	$ 24,579	$ 24,904	$ 6,931
Goodwill and core deposit intangible resulting from Premara merger	0		17,973
Adjustment of goodwill		(325)
Goodwill, Amortization Expense	0	0	0
Goodwill, Ending Balance	24,579	24,579	24,904
Core Deposit Intangible, Gross - Beginning Balance	5,919	5,919	3,219
Core Deposit Intangible, Gross - Goodwill and core deposit intangible resulting from Premara merger	350		2,700
Core Deposit Intangible, Gross - Adjustment of goodwill		0
Core Deposit Intangible, Gross - Amortization expense	0	0	0
Core Deposit Intangible, Gross - Ending Balance	6,269	5,919	5,919
Core Deposit Intangible, Accumulated Amortization - Beginning Balance	(3,834)	(2,818)	(2,409)
Core Deposit Intangible, Accumulated Amortization - Goodwill and core deposit intangible resulting from Premara merger	0		0
Core Deposit Intangible, Accumulated Amortization - Adjustment of goodwill		0
Core Deposit Intangible, Accumulated Amortization - Amortization expense	(825)	(1,016)	(409)
Core Deposit Intangible, Accumulated Amortization - Ending Balance	(4,659)	(3,834)	(2,818)
Finite-Lived Intangible Assets, Net, Beginning Balance	2,085	3,101	810
Core Deposit Intangible, Net - Goodwill and core deposit intangible resulting from Premara merger	350		2,700
Core Deposit Intangible, Net - Adjustment of goodwill		0
Core Deposit Intangible, Net - Amortization expense	(825)	(1,016)	(409)
Finite-Lived Intangible Assets, Net, Ending Balance	$ 1,610	$ 2,085	$ 3,101