SIGNIFICANT ACCOUNTING POLICIES - Schedule of Cash and Restricted Cash (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Cash and cash equivalents	$ 361,591	$ 182,581
Restricted cash	0	2,921
Total cash and cash equivalents and restricted cash	$ 361,591	$ 185,502	$ 112,700	$ 81,431