ACCUMULATED OTHER COMPREHENSIVE (LOSS) INCOME (Schedule of Components) (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	$ 1,556,873
Other comprehensive (loss) income before reclassifications	(29,836)	$ (12,979)
Amounts reclassified from accumulated other comprehensive (loss) income	86	(199)
Net other comprehensive (loss)/income	(29,750)	(13,178)
Ending balance	1,500,850	1,556,873
Accumulated Other Comprehensive (Loss) Income
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	239	13,417
Ending balance	(29,511)	239
Foreign currency translation (loss) gains
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(1,010)	15,975
Other comprehensive (loss) income before reclassifications	375	(16,985)
Amounts reclassified from accumulated other comprehensive (loss) income	0	0
Net other comprehensive (loss)/income	375	(16,985)
Ending balance	(635)	(1,010)
Net investment hedges of New Zealand subsidiary
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	1,321	1,665
Other comprehensive (loss) income before reclassifications	0	(344)
Amounts reclassified from accumulated other comprehensive (loss) income	0	0
Net other comprehensive (loss)/income	0	(344)
Ending balance	1,321	1,321
Cash flow hedges
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	21,965	16,184
Other comprehensive (loss) income before reclassifications	(30,211)	5,944
Amounts reclassified from accumulated other comprehensive (loss) income	(138)	(163)
Net other comprehensive (loss)/income	(30,349)	5,781
Ending balance	(8,384)	21,965
Cash flow hedges | Interest rate swaps
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Other comprehensive (loss) income before reclassifications	30,800
Employee benefit plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(22,037)	(20,407)
Other comprehensive (loss) income before reclassifications	0	(1,594)
Amounts reclassified from accumulated other comprehensive (loss) income	224	(36)
Net other comprehensive (loss)/income	224	(1,630)
Ending balance	$ (21,813)	$ (22,037)