THE COMPANY AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Allowance for Credit Losses and Revenue Reserve (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2020 USD ($)
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 19,066
Current period provision for credit losses	60,090
Write-offs charged against the allowance	(53,208)
Recoveries collected	1,883
Balance at end of period	$ 27,831