ACCUMULATED OTHER COMPREHENSIVE LOSS (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	$ 2,476,310	$ 2,536,568
Ending balance	2,159,092	2,607,706
Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(162,243)	(199,704)
Amortization	0	0
Other current period change	(65,878)	15,388
Ending balance	(228,121)	(184,316)
Net Actuarial Loss and Prior Service Costs
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(667,459)	(711,921)
Amortization	12,045	11,450
Other current period change	(3,452)	(7,203)
Ending balance	(658,866)	(707,674)
Unrealized Gain/Loss from Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(6,789)	(9)
Amortization	0	0
Other current period change	(10,864)	(7,389)
Ending balance	(17,653)	(7,398)
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(836,491)	(911,634)
Amortization	12,045	11,450
Other current period change	(80,194)	796
Ending balance	$ (904,640)	$ (899,388)