ACCUMULATED OTHER COMPREHENSIVE LOSS - Changes in Accumulated Other Comprehensive Loss by Component (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Components of Other Accumulated Income, Net of Tax [Roll Forward]
Balance beginning of period	$ 1,205,805	$ 1,269,813	$ 1,171,965	$ 1,169,756	$ 1,269,813	$ 1,169,756
Other comprehensive (loss) income before reclassifications and tax impacts					(46,293)
Amounts reclassified out of accumulated other comprehensive loss					3,228
Tax gain (loss)					1,287
Other comprehensive income (loss), net of tax	17,528	(59,306)	5,076	4,024	(41,778)	9,100
Balance ending of period	1,253,971	1,205,805	1,209,467	1,171,965	1,253,971	1,209,467
Foreign Currency Translation
Components of Other Accumulated Income, Net of Tax [Roll Forward]
Balance beginning of period		(187,795)			(187,795)
Other comprehensive (loss) income before reclassifications and tax impacts					(25,205)
Amounts reclassified out of accumulated other comprehensive loss					0
Tax gain (loss)					1,349
Other comprehensive income (loss), net of tax					(23,856)
Balance ending of period	(211,651)				(211,651)
Unrealized Gains (Losses) on Available-For-Sale Securities
Components of Other Accumulated Income, Net of Tax [Roll Forward]
Balance beginning of period		143			143
Other comprehensive (loss) income before reclassifications and tax impacts					294
Amounts reclassified out of accumulated other comprehensive loss					0
Tax gain (loss)					(62)
Other comprehensive income (loss), net of tax					232
Balance ending of period	375				375
Unrealized Loss on Interest Rate Hedge
Components of Other Accumulated Income, Net of Tax [Roll Forward]
Balance beginning of period		(20,839)			(20,839)
Other comprehensive (loss) income before reclassifications and tax impacts					(21,382)
Amounts reclassified out of accumulated other comprehensive loss					3,228
Tax gain (loss)					0
Other comprehensive income (loss), net of tax					(18,154)
Balance ending of period	(38,993)				(38,993)
Unfunded Pension Liability
Components of Other Accumulated Income, Net of Tax [Roll Forward]
Balance beginning of period		(1,560)			(1,560)
Other comprehensive (loss) income before reclassifications and tax impacts					0
Amounts reclassified out of accumulated other comprehensive loss					0
Tax gain (loss)					0
Other comprehensive income (loss), net of tax					0
Balance ending of period	(1,560)				(1,560)
Total
Components of Other Accumulated Income, Net of Tax [Roll Forward]
Balance beginning of period	(269,357)	(210,051)	(219,347)	(223,371)	(210,051)	(223,371)
Other comprehensive income (loss), net of tax	17,528	(59,306)	5,076	4,024
Balance ending of period	$ (251,829)	$ (269,357)	$ (214,271)	$ (219,347)	$ (251,829)	$ (214,271)