ACCUMULATED OTHER COMPREHENSIVE INCOME/(LOSS) (Schedule of Components) (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	$ 1,411,610
Other comprehensive income before reclassifications	4,977		$ 32,431
Amounts reclassified from accumulated other comprehensive income	(288)		(1,510)
Net other comprehensive income/(loss)	4,689		30,921
Recapitalization of New Zealand JV			0
Ending balance	1,560,500		1,411,610
Foreign currency translation gains/ (losses)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	8,559	$ (2,450)	(2,450)
Other comprehensive income before reclassifications	2,002		7,387
Amounts reclassified from accumulated other comprehensive income	0		0
Net other comprehensive income/(loss)	2,002		7,387
Recapitalization of New Zealand JV			3,622
Ending balance	10,561		8,559
Net investment hedges of New Zealand JV
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	1,665	6,271	6,271
Other comprehensive income before reclassifications	0		0
Amounts reclassified from accumulated other comprehensive income	0		(4,606)
Net other comprehensive income/(loss)	0		(4,606)
Recapitalization of New Zealand JV			0
Ending balance	1,665		1,665
Cash flow hedges
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	10,831	(11,592)	(11,592)
Other comprehensive income before reclassifications	2,975		22,024
Amounts reclassified from accumulated other comprehensive income	(404)		583
Net other comprehensive income/(loss)	2,571		22,607
Recapitalization of New Zealand JV			(184)
Ending balance	13,402		10,831
Employee benefit plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(20,199)	(25,732)	(25,732)
Other comprehensive income before reclassifications	0		3,020
Amounts reclassified from accumulated other comprehensive income	116		2,513
Net other comprehensive income/(loss)	116		5,533
Recapitalization of New Zealand JV			0
Ending balance	(20,083)		(20,199)
Annual computation of pension liabilities gain (loss)			2,400
Curtailment gain			5,400
Accumulated Other Comprehensive Income/(Loss)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	856	(33,503)	(33,503)
Recapitalization of New Zealand JV			3,438
Ending balance	$ 5,545		$ 856
Interest rate swaps | Cash flow hedges
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Other comprehensive income before reclassifications		$ 2,600