LEASES - Components of Lease Expense and Payments (Details) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019 USD ($)	Sep. 30, 2019 USD ($)
LEASES
Operating lease cost	$ 3,627	$ 11,294
Short-term lease cost	652	2,232
Variable lease cost	1,151	2,400
Total operating lease cost	5,430	15,926
Operating cash flows, which were included in the measurement of lease liabilities		10,200
Lease liabilities arising from right-of-use assets		7,300
Finance lease cost:
Amortization of right-of-use asset	570	1,749
Variable costs	244	802
Total finance lease cost	814	2,551
Finance leases cost included in property, plant and equipment	$ 25,900	$ 25,900
Property, plant and equipment	us-gaap:PropertyPlantAndEquipmentGross	us-gaap:PropertyPlantAndEquipmentGross
Accumulated depreciation related to finance leases	$ 8,800	$ 8,800