LEASES - Components of Lease Expense and Payments (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($)
LEASES
Operating lease cost	$ 3,516
Short-term lease cost	713
Variable lease cost	961
Total operating lease cost	5,190
Operating cash flows, which were included in the measurement of lease liabilities	3,200
Lease liabilities arising from right-of-use assets	200
Finance lease cost:
Amortization of right-of-use asset	593
Variable costs	296
Total finance lease cost	889
Finance leases cost included in property, plant and equipment	$ 27,400
Property, plant and equipment	us-gaap:PropertyPlantAndEquipmentGross
Accumulated depreciation related to finance leases	$ 7,900