COMPREHENSIVE INCOME - Schedule of Changes in Accumulated Other Comprehensive Income by Component (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2017 USD ($)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	$ 839,667
Other comprehensive (loss) income	19,955
Amounts reclassified from accumulated other comprehensive income	3,041
Net current-period other comprehensive (loss) income	22,996
Ending balance	894,555
Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	1,071
Other comprehensive (loss) income	(559)
Amounts reclassified from accumulated other comprehensive income	22
Net current-period other comprehensive (loss) income	(537)
Ending balance	534
Defined Benefit Pension Items
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(36)
Other comprehensive (loss) income	(15)
Amounts reclassified from accumulated other comprehensive income	0
Net current-period other comprehensive (loss) income	(15)
Ending balance	(51)
Foreign Currency Items
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(58,189)
Other comprehensive (loss) income	23,548
Amounts reclassified from accumulated other comprehensive income	0
Net current-period other comprehensive (loss) income	23,548
Ending balance	(34,641)
Short-term Investment
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	0
Other comprehensive (loss) income	(3,019)
Amounts reclassified from accumulated other comprehensive income	3,019
Net current-period other comprehensive (loss) income	0
Ending balance	0
Total
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(57,154)
Ending balance	$ (34,158)