OTHER CONSOLIDATED BALANCE SHEET COMPONENTS (CURRENT) - Schedule of Reserve for Transaction Losses (Details) - Transaction Losses - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Loss Contingency Accrual [Roll Forward]
Accrued transaction losses, beginning of the year	$ 33,682	$ 26,893
Provision for transaction losses	79,414	64,981
Charge-offs to accrued transaction losses	(78,325)	(58,192)
Accrued transaction losses, end of the year	$ 34,771	$ 33,682