GOODWILL AND INTANGIBLE ASSETS- Schedule of balance of intangible assets, net (Details ) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	$ 903,227	$ 903,227
Accumulated impairment losses	(483,088)	(483,088)
Net goodwill	420,139	420,139
Intangible assets with indefinite lives	10,142	10,142
Intangible assets with definite lives, net	85,392	118,360
Total intangible assets, net	$ 95,534	$ 128,502