ACCUMULATED OTHER COMPREHENSIVE LOSS - Changes in Accumulated Other Comprehensive Loss by Component (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Components of Other Accumulated Income, Net of Tax [Roll Forward]
Balance beginning of period	$ 1,269,813	$ 1,169,756
Other comprehensive loss before reclassifications	(61,770)
Amounts reclassified out of accumulated other comprehensive loss	1,098
Tax gain	1,366
Other comprehensive (loss) income, net of tax	(59,306)	4,024
Balance ending of period	1,205,805	1,171,965
Foreign Currency Translation
Components of Other Accumulated Income, Net of Tax [Roll Forward]
Balance beginning of period	(187,795)
Other comprehensive loss before reclassifications	(43,307)
Amounts reclassified out of accumulated other comprehensive loss	0
Tax gain	1,349
Other comprehensive (loss) income, net of tax	(41,958)
Balance ending of period	(229,753)
Unrealized (Losses) Gains on Available-For-Sale Securities
Components of Other Accumulated Income, Net of Tax [Roll Forward]
Balance beginning of period	143
Other comprehensive loss before reclassifications	(81)
Amounts reclassified out of accumulated other comprehensive loss	0
Tax gain	17
Other comprehensive (loss) income, net of tax	(64)
Balance ending of period	79
Unrealized Loss on Interest Rate Hedge
Components of Other Accumulated Income, Net of Tax [Roll Forward]
Balance beginning of period	(20,839)
Other comprehensive loss before reclassifications	(18,382)
Amounts reclassified out of accumulated other comprehensive loss	1,098
Tax gain	0
Other comprehensive (loss) income, net of tax	(17,284)
Balance ending of period	(38,123)
Unfunded Pension Liability
Components of Other Accumulated Income, Net of Tax [Roll Forward]
Balance beginning of period	(1,560)
Other comprehensive loss before reclassifications	0
Amounts reclassified out of accumulated other comprehensive loss	0
Tax gain	0
Other comprehensive (loss) income, net of tax	0
Balance ending of period	(1,560)
Total
Components of Other Accumulated Income, Net of Tax [Roll Forward]
Balance beginning of period	(210,051)	(223,371)
Other comprehensive (loss) income, net of tax	(59,306)	4,024
Balance ending of period	$ (269,357)	$ (219,347)