ACCUMULATED OTHER COMPREHENSIVE INCOME (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Accumulated other comprehensive income activity
Balance at the beginning of the period	$ 1,571,916
Balance at the end of the period	1,587,290
Foreign Currency
Accumulated other comprehensive income activity
Balance at the beginning of the period	(257,124)	$ (248,401)
Other comprehensive income (loss) before reclassifications	(42,229)	(9,619)
Net current-period other comprehensive income (loss)	(42,229)	(9,619)
Balance at the end of the period	(299,353)	(258,020)
Defined Benefit Pension Plans
Accumulated other comprehensive income activity
Balance at the beginning of the period	(83,147)	(60,463)
Amounts reclassified from accumulated other comprehensive income	1,636	721
Net current-period other comprehensive income (loss)	1,636	721
Balance at the end of the period	(81,511)	(59,742)
Derivatives
Accumulated other comprehensive income activity
Balance at the beginning of the period	(1,677)	(1,640)
Other comprehensive income (loss) before reclassifications	5,026	5,738
Amounts reclassified from accumulated other comprehensive income	(3,543)	(6,131)
Net current-period other comprehensive income (loss)	1,483	(393)
Balance at the end of the period	(194)	(2,033)
Accumulated Other Comprehensive Income/(Loss)
Accumulated other comprehensive income activity
Balance at the beginning of the period	(341,948)	(310,504)
Other comprehensive income (loss) before reclassifications	(37,203)	(3,881)
Amounts reclassified from accumulated other comprehensive income	(1,907)	(5,410)
Net current-period other comprehensive income (loss)	(39,110)	(9,291)
Balance at the end of the period	$ (381,058)	$ (319,795)