ACCUMULATED OTHER COMPREHENSIVE INCOME - Changes in Accumulated Other Comprehensive Income by Component (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Accumulated other comprehensive income activity
Balance at the beginning of the period	$ 1,850,389
Other comprehensive (loss) income before reclassifications	(43,102)	$ (37,203)
Amounts reclassified from accumulated other comprehensive income (loss)	(2,154)	(1,907)
Net current-period other comprehensive (loss) income	(45,256)	(39,110)
Balance at the end of the period	1,900,412
Foreign Currency
Accumulated other comprehensive income activity
Balance at the beginning of the period	(178,025)	(257,124)
Other comprehensive (loss) income before reclassifications	(48,482)	(42,229)
Amounts reclassified from accumulated other comprehensive income (loss)	0	0
Net current-period other comprehensive (loss) income	(48,482)	(42,229)
Balance at the end of the period	(226,507)	(299,353)
Defined Benefit Pension Plans
Accumulated other comprehensive income activity
Balance at the beginning of the period	(102,322)	(83,147)
Other comprehensive (loss) income before reclassifications	319	0
Amounts reclassified from accumulated other comprehensive income (loss)	2,387	1,636
Net current-period other comprehensive (loss) income	2,706	1,636
Balance at the end of the period	(99,616)	(81,511)
Derivatives
Accumulated other comprehensive income activity
Balance at the beginning of the period	(1,362)	(1,677)
Other comprehensive (loss) income before reclassifications	5,061	5,026
Amounts reclassified from accumulated other comprehensive income (loss)	(4,541)	(3,543)
Net current-period other comprehensive (loss) income	520	1,483
Balance at the end of the period	(842)	(194)
Accumulated Other Comprehensive Income/(Loss)
Accumulated other comprehensive income activity
Balance at the beginning of the period	(281,709)	(341,948)
Balance at the end of the period	$ (326,965)	$ (381,058)