COMPREHENSIVE INCOME - Schedule of Changes in Accumulated Other Comprehensive Income by Component (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance, Beginning of Period	$ 1,375,796	$ 962,306
Other comprehensive income (loss)	(4,484)
Less: Amounts reclassified from accumulated other comprehensive income	6,752
Net current-period other comprehensive income (loss)	(11,236)	21,612
Balance, End of Period	1,397,030	998,440
Gains and Losses on Derivatives
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance, Beginning of Period	(4,813)
Other comprehensive income (loss)	2,516
Less: Amounts reclassified from accumulated other comprehensive income	6,752
Net current-period other comprehensive income (loss)	(4,236)
Balance, End of Period	(9,049)
Defined Benefit Pension Items
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance, Beginning of Period	(736)
Other comprehensive income (loss)	9
Less: Amounts reclassified from accumulated other comprehensive income	0
Net current-period other comprehensive income (loss)	9
Balance, End of Period	(727)
Foreign Currency Items
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance, Beginning of Period	(39,894)
Other comprehensive income (loss)	(7,009)
Less: Amounts reclassified from accumulated other comprehensive income	0
Net current-period other comprehensive income (loss)	(7,009)
Balance, End of Period	(46,903)
Total
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance, Beginning of Period	(45,443)	(23,807)
Net current-period other comprehensive income (loss)	(11,236)	22,144
Balance, End of Period	$ (56,679)	$ (1,663)