FAIR VALUE - IMPAIRED LOANS (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Impaired loans
Carrying amount of loans measured at fair value	$ 27,935	$ 27,076
Valuation allowance	(4,579)	(4,685)
Nonrecurring basis
Impaired loans
Total fair value	7,002	6,103
Fair Value, Inputs, Level 3 | Nonrecurring basis
Impaired loans
Carrying amount of loans measured at fair value	6,293	5,358
Estimated selling costs considered in carrying amount	725	752
Valuation allowance	(16)	(7)
Total fair value	7,002	6,103
Provision for impairment on loan, lease and other losses
Provisions on collateral-dependent, impaired loans	$ 429	$ 8