ACCUMULATED OTHER COMPREHENSIVE LOSS (Components of AOCI) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Increase (Decrease) in Equity
Other comprehensive loss before reclassifications	$ 41,966	$ 23,648	$ (144,057)
Amounts reclassified out of accumulated other comprehensive loss	222	0	0
Tax effects	(269)	16,918	7
Other comprehensive loss	41,919	40,566	(144,050)
Foreign Currency Translation Adjustments
Increase (Decrease) in Equity
Beginning balance	(212,211)	(252,939)	(108,889)
Other comprehensive loss before reclassifications	41,636	23,967	(144,050)
Amounts reclassified out of accumulated other comprehensive loss	0	0	0
Tax effects	0	16,761	0
Other comprehensive loss	41,636	40,728	(144,050)
Ending balance	(170,575)	(212,211)	(252,939)
Unrealized (Losses) Gains on Available-for-Sale Securities
Increase (Decrease) in Equity
Beginning balance	(321)	0	0
Other comprehensive loss before reclassifications	184	(535)	0
Amounts reclassified out of accumulated other comprehensive loss	222	0	0
Tax effects	(231)	214	0
Other comprehensive loss	175	(321)	0
Ending balance	(146)	(321)	0
Unfunded Pension Liability
Increase (Decrease) in Equity
Beginning balance	(1,794)	(1,953)	(1,953)
Other comprehensive loss before reclassifications	146	216	(7)
Amounts reclassified out of accumulated other comprehensive loss	0	0	0
Tax effects	(38)	(57)	7
Other comprehensive loss	108	159	0
Ending balance	(1,686)	(1,794)	(1,953)
Accumulated Other Comprehensive loss
Increase (Decrease) in Equity
Beginning balance	(214,326)	(254,892)	(110,842)
Ending balance	$ (172,407)	$ (214,326)	$ (254,892)