SIGNIFICANT ACCOUNTING POLICIES - RECOGNITION OF REVENUES AND EXPENSES (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Total	$ 437.3	$ 419.2	$ 1,223.2	$ 1,181.9
Total	152.1	124.7	434.7	348.9
Ocean Transportation
Ocean Transportation services	431.4	414.1	1,207.3	1,167.3
Terminal and other related services	0.7	0.6	2.0	2.2
Fuel sales	3.5	2.8	8.7	7.3
Ship management services and related costs	1.7	1.7	5.2	5.1
Total	437.3	419.2	$ 1,223.2	$ 1,181.9
Percentage of ocean transportation revenues and fuel sales denominated in foreign currency			3.00%	3.00%
Logistics
Transportation Brokerage and Freight Forwarding Services	135.4	110.1	$ 391.0	$ 309.3
Warehouse and distribution services	8.9	7.8	24.1	22.3
Supply chain management and other services	7.8	6.8	19.6	17.3
Total	$ 152.1	$ 124.7	$ 434.7	$ 348.9
Percentage of transportation brokerage and freight forwarding services revenue denominated in forgeign currency			3.00%	3.00%