LEASES - Amounts Recognized in the Balance Sheet for Leases (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Operating Leases:
Operating lease right-of-use assets	$ 68,183	$ 63,869
Current portion of operating lease obligations	17,044	17,375
Operating lease obligations (non-current)	$ 56,701	$ 52,207
Weighted average remaining lease term, operating leases	6 years	6 years
Weighted average discount rate, operating leases	6.80%	6.70%
Finance Leases:
Property, plant and equipment, net	$ 4,679	$ 4,779
Current portion of long-term debt and finance lease obligations	352	337
Long-term debt and finance lease obligations	$ 4,741	$ 4,816
Weighted average remaining lease term	12 years	12 years
Weighted average discount rate	6.20%	6.20%