COMMITMENTS AND CONTINGENCIES - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Variable Interest Entity [Line Items]
Operating leases, rent expense	$ 4,157,000	$ 4,979,000	$ 4,953,000
Minimum
Variable Interest Entity [Line Items]
Loss contingency, range of possible loss	0.0
Maximum
Variable Interest Entity [Line Items]
Loss contingency, range of possible loss	3,300,000
Repauno
Variable Interest Entity [Line Items]
Potential milestone payment	15,000,000.0
Long Ridge Seller
Variable Interest Entity [Line Items]
Potential milestone payment	$ 5,000,000.0