ACCUMULATED OTHER COMPREHENSIVE INCOME (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Accumulated other comprehensive income activity
Balance at the beginning of the period	$ 1,173,950
Balance at the end of the period	1,308,877
Foreign Currency
Accumulated other comprehensive income activity
Balance at the beginning of the period	(259,888)	$ (206,725)
Other comprehensive income (loss) before reclassifications	51,595	30,454
Net current-period other comprehensive income (loss)	51,595	30,454
Balance at the end of the period	(208,293)	(176,271)
Defined Benefit Pension Plans
Accumulated other comprehensive income activity
Balance at the beginning of the period	(59,775)	(55,550)
Amounts reclassified from accumulated other comprehensive income	1,775	1,674
Net current-period other comprehensive income (loss)	1,775	1,674
Balance at the end of the period	(58,000)	(53,876)
Other
Accumulated other comprehensive income activity
Balance at the beginning of the period	(46)	(72)
Amounts reclassified from accumulated other comprehensive income	14	13
Net current-period other comprehensive income (loss)	14	13
Balance at the end of the period	(32)	(59)
Accumulated Other Comprehensive Income/(Loss)
Accumulated other comprehensive income activity
Balance at the beginning of the period	(319,709)	(262,347)
Other comprehensive income (loss) before reclassifications	51,595	30,454
Amounts reclassified from accumulated other comprehensive income	1,789	1,687
Net current-period other comprehensive income (loss)	53,384	32,141
Balance at the end of the period	$ (266,325)	$ (230,206)