THE COMPANY AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Reconciliation of Cash, Cash Equivalents, and Restricted Cash (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Cash and cash equivalents	$ 1,644,829	$ 1,630,809	$ 1,522,300	$ 1,329,187
Restricted cash included in other current assets	347	2,873	331	20,464
Restricted cash included in other assets	0	0	0	10,548
Total cash, cash equivalents and restricted cash as shown on the consolidated statement of cash flows	$ 1,645,176	$ 1,633,682	$ 1,522,631	$ 1,360,199