SECURITIES SOLD UNDER REPURCHASE AGREEMENTS - Summary of Securities Sold Under Repurchase Agreements (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Assets Sold under Agreements to Repurchase [Line Items]
Securities sold under agreements to repurchase	$ 20,384	$ 30,638
Weighted Average
Assets Sold under Agreements to Repurchase [Line Items]
Securities sold under agreements to repurchase	$ 15,692	$ 28,694	$ 44,324
Average interest rate during the year	0.15%	0.20%	0.22%
Weighted average interest rate at year-end	0.14%	0.18%	0.19%
Maximum
Assets Sold under Agreements to Repurchase [Line Items]
Securities sold under agreements to repurchase	$ 23,270	$ 49,836	$ 56,203