ACCUMULATED OTHER COMPREHENSIVE LOSS (Changes in Accumulated Other Comprehensive Loss by Component) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($)
Components of Other Accumulated Income, Net of Tax [Roll Forward]
Balance at beginning of period	$ 1,169,756
Other comprehensive income (loss) before tax effects	3,697
Tax impact related to items in other comprehensive income (loss)	(31)
Amounts reclassified out of accumulated other comprehensive loss	358
Other comprehensive income	4,024
Balance at end of period	1,171,965
Foreign Currency Translation
Components of Other Accumulated Income, Net of Tax [Roll Forward]
Balance at beginning of period	(212,925)
Other comprehensive income (loss) before tax effects	8,540
Tax impact related to items in other comprehensive income (loss)	0
Amounts reclassified out of accumulated other comprehensive loss	0
Other comprehensive income	8,540
Balance at end of period	(204,385)
Unrealized Losses (Gains) on Available-For-Sale Securities
Components of Other Accumulated Income, Net of Tax [Roll Forward]
Balance at beginning of period	(69)
Other comprehensive income (loss) before tax effects	174
Tax impact related to items in other comprehensive income (loss)	(31)
Amounts reclassified out of accumulated other comprehensive loss	0
Other comprehensive income	143
Balance at end of period	74
Unrealized Losses on Interest Rate Hedge
Components of Other Accumulated Income, Net of Tax [Roll Forward]
Balance at beginning of period	(8,773)
Other comprehensive income (loss) before tax effects	(5,017)
Tax impact related to items in other comprehensive income (loss)	0
Amounts reclassified out of accumulated other comprehensive loss	358
Other comprehensive income	(4,659)
Balance at end of period	(13,432)
Unfunded Pension Liability
Components of Other Accumulated Income, Net of Tax [Roll Forward]
Balance at beginning of period	(1,604)
Other comprehensive income (loss) before tax effects	0
Tax impact related to items in other comprehensive income (loss)	0
Amounts reclassified out of accumulated other comprehensive loss	0
Other comprehensive income	0
Balance at end of period	(1,604)
Total
Components of Other Accumulated Income, Net of Tax [Roll Forward]
Balance at beginning of period	(223,371)
Balance at end of period	$ (219,347)