ACCUMULATED OTHER COMPREHENSIVE LOSS (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	$ 2,841,671
Amortization	10,756	$ 10,269
Other current period change	(30,655)	43,543
Adoption of new accounting standard	(100,567)
Ending balance	2,841,403
Currency Translation Adjustments and Other
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(140,438)	(206,610)
Amortization	0	0
Other current period change	(29,752)	43,343
Adoption of new accounting standard	0
Ending balance	(170,190)	(163,267)
Net Actuarial Loss
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(560,153)	(620,292)
Amortization	10,587	10,159
Other current period change	(903)	200
Adoption of new accounting standard	(98,987)
Ending balance	(649,456)	(609,933)
Prior Service (Cost)/ Credit
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(6,910)	(7,130)
Amortization	169	110
Other current period change	0	0
Adoption of new accounting standard	(1,580)
Ending balance	(8,321)	(7,020)
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(707,501)	(834,032)
Ending balance	$ (827,967)	$ (780,220)