DERIVATIVE FINANCIAL INSTRUMENTS - Narrative (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Derivative [Line Items]
Ineffectiveness included in net income			$ 0		$ 0
Interest expense	$ 5,446,000	$ 3,063,000	13,679,000	$ 8,951,000
Unrealized loss to be reclassified as a reduction of interest expense			0
Designated as Hedging Instrument | Cash Flow Hedging | Interest Rate Swap
Derivative [Line Items]
Notional amount	$ 5,000,000		5,000,000		$ 5,000,000
Interest expense			$ 516,000	$ 559,000