LONG-TERM LIABILITIES - Schedule of Long-Term Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Other Liabilities [Abstract]
Capital lease obligations	$ 837	$ 124
Deferred rent	1,359	1,812
Restructuring	10,176	1,267
Pension obligations	7,524	0
Taxes payable	2,079	0
Other	2,544	790
Long-term liabilities	24,519	3,993
Current portion	(11,330)	(2,360)
Long-term liabilities, net of current portion	$ 13,189	$ 1,633