OTHER NON-CURRENT ASSETS (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Other Assets, Noncurrent Disclosure [Abstract]
Escrow deposit	$ 28,750	$ 0
Cost-method investments	0	8,000
Other	2,589	2,992
Total other non-current assets	$ 31,339	$ 10,992