ACCUMULATED OTHER COMPREHENSIVE (LOSS) INCOME (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Components of accumulated other comprehensive loss:
Balance at the beginning of the period	$ 3,034	$ 32,387
Other comprehensive (loss) income before reclassifications	(19,856)	(21,051)
Net current-period other comprehensive (loss) income	(19,856)	(21,051)
Balance at the end of the period	(16,822)	53,438
Currency Translation Gains (Losses)
Components of accumulated other comprehensive loss:
Balance at the beginning of the period	2,950	(32,581)
Other comprehensive (loss) income before reclassifications	(19,696)	(21,555)
Net current-period other comprehensive (loss) income	(19,696)	(21,555)
Balance at the end of the period	(16,746)	(54,136)
Unrealized Gains (Losses) on Available-for-Sale Securities
Components of accumulated other comprehensive loss:
Balance at the beginning of the period	84	194
Other comprehensive (loss) income before reclassifications	(160)	504
Net current-period other comprehensive (loss) income	(160)	504
Balance at the end of the period	$ (76)	$ 698