SIGNIFICANT ACCOUNTING POLICIES - REVENUES AND EXPENES (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Total	$ 379.3	$ 370.0
Total	132.1	104.4
Ocean Transportation
Ocean transportation services	374.7	365.0
Terminal and other related services	0.8	0.8
Fuel sales	2.1	2.5
Ship management services	1.7	1.7
Total	$ 379.3	$ 370.0
Percentage of ocean transportation revenues and fuel sales denominated in foreign currency	3.00%	3.00%
Logistics
Transportation brokerage and freight forwarding services	$ 119.2	$ 92.3
Warehouse and distribution services	7.4	7.2
Supply chain management and other services	5.5	4.9
Total	$ 132.1	$ 104.4
Percentage of transportation brokerage and freight forwarding services revenue denominated in forgeign currency	3.00%	3.00%