ACCUMULATED OTHER COMPREHENSIVE INCOME (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Accumulated other comprehensive income activity
Balance at the beginning of the period	$ 1,422,556
Balance at the end of the period	1,553,656
Foreign Currency
Accumulated other comprehensive income activity
Balance at the beginning of the period	(248,401)	$ (185,503)
Other comprehensive income (loss) before reclassifications	(42,725)	(53,141)
Net current-period other comprehensive income (loss)	(42,725)	(53,141)
Balance at the end of the period	(291,126)	(238,644)
Defined Benefit Pension Plans
Accumulated other comprehensive income activity
Balance at the beginning of the period	(60,463)	(64,595)
Amounts reclassified from accumulated other comprehensive income	2,150	4,032
Net current-period other comprehensive income (loss)	2,150	4,032
Balance at the end of the period	(58,313)	(60,563)
Derivatives
Accumulated other comprehensive income activity
Balance at the beginning of the period	(1,640)	(3,204)
Other comprehensive income (loss) before reclassifications	11,806	12,507
Amounts reclassified from accumulated other comprehensive income	(12,399)	(11,444)
Net current-period other comprehensive income (loss)	(593)	1,063
Balance at the end of the period	(2,233)	(2,141)
Accumulated Other Comprehensive Income/(Loss)
Accumulated other comprehensive income activity
Balance at the beginning of the period	(310,504)	(253,302)
Other comprehensive income (loss) before reclassifications	(30,919)	(40,634)
Amounts reclassified from accumulated other comprehensive income	(10,249)	(7,412)
Net current-period other comprehensive income (loss)	(41,168)	(48,046)
Balance at the end of the period	$ (351,672)	$ (301,348)