FAIR VALUE - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Additional provision for loan losses	$ 400	$ 200	$ 400	$ 800	$ 10,400	$ 1,900	$ 950	$ 800	$ 1,800	$ 14,050	$ 5,550
Assets measured at fair value on non-recurring basis
Outstanding balance of impaired loans with an allowance recorded	2,721				1,708				2,721	1,708	66
Valuation allowance on impaired loans	189				1,708				189	1,708	$ 1
Other real estate owned valuation allowance	0								0
Real estate owned additional provision									0
Non-recurring basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Additional provision for loan losses									200	1,700
Assets measured at fair value on non-recurring basis
Outstanding balance of impaired loans with an allowance recorded					1,700					1,700
Valuation allowance on impaired loans					1,700					1,700
Carrying Amount | Non-recurring basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying amount of impaired loans	$ 2,532				$ 0				$ 2,532	$ 0