CONSOLIDATED FINANCIAL STATEMENT DETAILS - Cash, Cash Equivalents, and Restricted Cash (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2020	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Cash and cash equivalents	$ 511,311	$ 739,164	$ 398,884	$ 465,676
Restricted cash included in other current assets	131	138	132	127
Cash, cash equivalents, and restricted cash included in current assets of discontinued operations	0	0	0	2,674,146
Restricted cash included in non-current assets of discontinued operations	0	0	0	409
Total cash, cash equivalents, and restricted cash as shown on the consolidated statement of cash flows	$ 511,442	$ 739,302	$ 399,016	$ 3,140,358