ACCUMULATED OTHER COMPREHENSIVE INCOME (Schedule of Components) (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	$ 1,593,023
Other comprehensive (loss)/income before reclassifications	3,855	$ 14,064
Amounts reclassified from accumulated other comprehensive income	(671)	(1,503)
Net other comprehensive (loss)/income	3,184	12,561
Ending balance	1,613,489	1,593,023
Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	13,417	856
Ending balance	16,601	13,417
Foreign currency translation gains
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	15,975	8,559
Other comprehensive (loss)/income before reclassifications	(14,907)	7,416
Amounts reclassified from accumulated other comprehensive income	0	0
Net other comprehensive (loss)/income	(14,907)	7,416
Ending balance	1,068	15,975
Net investment hedges of New Zealand JV
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	1,665	1,665
Other comprehensive (loss)/income before reclassifications	(344)	0
Amounts reclassified from accumulated other comprehensive income	0	0
Net other comprehensive (loss)/income	(344)	0
Ending balance	1,321	1,665
Cash flow hedges
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	16,184	10,831
Other comprehensive (loss)/income before reclassifications	19,106	7,321
Amounts reclassified from accumulated other comprehensive income	(1,009)	(1,968)
Net other comprehensive (loss)/income	18,097	5,353
Ending balance	34,281	16,184
Cash flow hedges | Interest rate swaps
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Other comprehensive (loss)/income before reclassifications	21,300
Employee benefit plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(20,407)	(20,199)
Other comprehensive (loss)/income before reclassifications	0	(673)
Amounts reclassified from accumulated other comprehensive income	338	465
Net other comprehensive (loss)/income	338	(208)
Ending balance	$ (20,069)	$ (20,407)