REVENUE - Changes in Contract Liability (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Revenue from Contract with Customer [Abstract]
Balance as of beginning of period	$ 629,739	$ 603,687
Recognized as revenue during period from beginning balance	(59,031)	(59,280)
Consideration deferred during period, net	51,759	66,714
Foreign currency translation adjustment and other	709	(4,585)
Balance as of end of period	$ 623,176	$ 606,536