SIGNIFICANT ACCOUNTING POLICIES - Schedule of Cash and Restricted Cash (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accounting Policies [Abstract]
Cash and cash equivalents	$ 182,581	$ 77,580	$ 85,814
Restricted cash	2,921	3,851	7,402
Total cash and cash equivalents and restricted cash	$ 185,502	$ 81,431	$ 93,216	$ 61,802