ALLOWANCE FOR CREDIT LOSSES - NARRATIVE (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Provision for credit losses	$ (25,051)	$ (20,406)	$ (61,796)	$ (44,339)
Allowance for credit losses	37,752	60,909	37,752	60,909	$ 35,253	$ 34,092	$ 41,055	$ 17,122
Transaction-based revenues
Disaggregation of Revenue [Line Items]
Provision for credit losses	24,700	20,100	59,600	43,400
Allowance for credit losses	35,000	60,500	35,000	60,500
Other revenues
Disaggregation of Revenue [Line Items]
Provision for credit losses	300	300	2,200	900
Allowance for credit losses	$ 2,800	$ 400	$ 2,800	$ 400