ALLOWANCE FOR CREDIT LOSSES - ALLOWANCE FOR CREDIT LOSSES OF RECEIVABLES FROM USERS (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Contract with Customer, Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 35,253	$ 41,055	$ 34,092	$ 17,122
Provision for credit losses	25,051	20,406	61,796	44,339
Write-offs	(22,552)	(552)	(58,136)	(552)
Ending balance	$ 37,752	$ 60,909	$ 37,752	$ 60,909