ACCUMULATED OTHER COMPREHENSIVE LOSS (Changes in Accumulated Other Comprehensive Loss by Component) (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2017 USD ($)
Components of Other Accumulated Income, Net of Tax [Roll Forward]
Balance at beginning of period	$ 1,084,241
Other comprehensive income before reclassifications	21,128
Amounts reclassified out of accumulated other comprehensive loss	222
Tax effects	(201)
Other comprehensive income	21,149
Balance at end of period	1,100,937
Foreign Currency Translation
Components of Other Accumulated Income, Net of Tax [Roll Forward]
Balance at beginning of period	(212,211)
Other comprehensive income before reclassifications	20,847
Amounts reclassified out of accumulated other comprehensive loss	0
Tax effects
Other comprehensive income	20,847
Balance at end of period	(191,364)
Unrealized Gains on Available-For-Sale Securities
Components of Other Accumulated Income, Net of Tax [Roll Forward]
Balance at beginning of period	(321)
Other comprehensive income before reclassifications	281
Amounts reclassified out of accumulated other comprehensive loss	222
Tax effects	(201)
Other comprehensive income	302
Balance at end of period	(19)
Unfunded Pension Liability
Components of Other Accumulated Income, Net of Tax [Roll Forward]
Balance at beginning of period	(1,794)
Other comprehensive income before reclassifications	0
Amounts reclassified out of accumulated other comprehensive loss	0
Tax effects	0
Other comprehensive income	0
Balance at end of period	(1,794)
Total
Components of Other Accumulated Income, Net of Tax [Roll Forward]
Balance at beginning of period	(214,326)
Balance at end of period	$ (193,177)