LEASES - Amounts Recognized in the Balance Sheet for Leases (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Leases [Abstract]
Operating lease right-of-use assets	$ 66,500	$ 66,555	$ 0
Current portion of operating lease obligations	17,314	17,770	0
Operating lease obligations (non-current)	53,945	$ 54,477	0
Property, plant and equipment, net	5,336		5,200
Current portion of long-term debt and finance lease obligations	279		$ 569
Long-term debt and finance lease obligations	$ 5,174
Weighted average remaining lease term, operating leases	6 years
Weighted average remaining lease term, finance leases	14 years
Weighted average discount rate, operating leases	8.40%
Weighted average discount rate, finance leases	6.30%