THE COMPANY AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Allowance for Credit Losses and Revenue Reserve (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2020 USD ($)
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 19,066
Current period provision for credit losses	39,338
Write-offs charged against the allowance	(33,700)
Recoveries collected	1,283
Balance at end of period	$ 25,987