ACCUMULATED OTHER COMPREHENSIVE LOSS (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2017 USD ($)
Components of accumulated other comprehensive loss:
Balance at the beginning of the period	$ 23,249
Net current-period other comprehensive loss (gain)	(7,716)
Balance at the end of the period	15,533
Currency Translation Losses
Components of accumulated other comprehensive loss:
Balance at the beginning of the period	23,056
Net current-period other comprehensive loss (gain)	(7,641)
Balance at the end of the period	15,415
Unrealized (Gains) Losses on Available-for-Sale Securities
Components of accumulated other comprehensive loss:
Balance at the beginning of the period	193
Net current-period other comprehensive loss (gain)	(75)
Balance at the end of the period	$ 118