GOODWILL AND INTANGIBLE ASSETS - INTANGIBLE ASSETS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Finite-lived Intangible Assets
Gross Amount at the beginning of the period	$ 10.4	$ 10.4
Additions	141.0
Gross Amount at the end of the period	151.4	10.4	$ 10.4
Accumulated Amortization	(12.3)	(7.9)
Net Amount	139.1	2.5
Aggregate intangible asset amortization	4.4	1.3	0.8
Estimated amortization expenses related to intangibles
2016	7.4
2017	7.4
2018	7.2
2019	7.0
2020	7.0
Thereafter	103.1
Net Amount	139.1	2.5
Ocean Transportation
Finite-lived Intangible Assets
Gross Amount at the beginning of the period	0.6	0.6
Gross Amount at the end of the period	140.6	0.6	0.6
Accumulated Amortization	(4.2)	(0.3)
Net Amount	136.4	0.3
Estimated amortization expenses related to intangibles
Net Amount	136.4	0.3
Ocean Transportation | Horizon
Finite-lived Intangible Assets
Additions	$ 140.0
Ocean Transportation | Customer Relationships. | Horizon
Estimated amortization expenses related to intangibles
Expected useful life	21 years
Logistics
Finite-lived Intangible Assets
Gross Amount at the beginning of the period	$ 9.8	9.8
Additions	1.0
Gross Amount at the end of the period	12.0	9.8	$ 9.8
Accumulated Amortization	(8.1)	(7.6)
Net Amount	2.7	2.2
Estimated amortization expenses related to intangibles
Net Amount	$ 2.7	$ 2.2