REVENUE RECOGNITION - Activity in the Liability of Customer Credits (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2021 USD ($)
Customer Credits [Roll Forward]
Customer credits, beginning balance	$ 61,006
Credits issued	173,476
Credits redeemed	(134,147)
Breakage revenue recognized	(21,084)
Foreign currency translation	(1,034)
Customer credits, ending balance	$ 78,217