ACCUMULATED OTHER COMPREHENSIVE INCOME (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accumulated other comprehensive income activity
Balance at the beginning of the period	$ 1,422,556
Balance at the end of the period	1,571,916	$ 1,422,556
Foreign Currency
Accumulated other comprehensive income activity
Balance at the beginning of the period	(248,401)	(185,503)	$ (259,888)
Other comprehensive income (loss) before reclassifications	(8,723)	(62,898)	74,385
Net current-period other comprehensive income (loss)	(8,723)	(62,898)	74,385
Balance at the end of the period	(257,124)	(248,401)	(185,503)
Defined Benefit Pension Plans
Accumulated other comprehensive income activity
Balance at the beginning of the period	(60,463)	(64,595)	(59,775)
Other comprehensive income (loss) before reclassifications	(25,557)	5,266	(8,944)
Amounts reclassified from accumulated other comprehensive income	2,873	5,524	4,124
Net current-period other comprehensive income (loss)	(22,684)	10,790	(4,820)
Balance at the end of the period	(83,147)	(60,463)	(64,595)
Defined Benefit Pension Plans \| Accounting Standards Update 2018-02
Accumulated other comprehensive income activity
Adoption of accounting standards		(6,658)
Derivatives
Accumulated other comprehensive income activity
Balance at the beginning of the period	(1,640)	(3,204)	(46)
Other comprehensive income (loss) before reclassifications	8,026	16,624	(11,806)
Amounts reclassified from accumulated other comprehensive income	(8,063)	(15,060)	8,648
Net current-period other comprehensive income (loss)	(37)	1,564	(3,158)
Balance at the end of the period	(1,677)	(1,640)	(3,204)
Accumulated Other Comprehensive Income/(Loss)
Accumulated other comprehensive income activity
Balance at the beginning of the period	(310,504)	(253,302)	(319,709)
Other comprehensive income (loss) before reclassifications	(26,254)	(41,008)	53,635
Amounts reclassified from accumulated other comprehensive income	(5,190)	(9,536)	12,772
Net current-period other comprehensive income (loss)	(31,444)	(50,544)	66,407
Balance at the end of the period	$ (341,948)	(310,504)	$ (253,302)
Accumulated Other Comprehensive Income/(Loss) \| Accounting Standards Update 2018-02
Accumulated other comprehensive income activity
Adoption of accounting standards		$ (6,658)

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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