PROPERTY AND EQUIPMENT - SUMMARY (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($) item	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Property and equipment
Cost	$ 2,615.2	$ 2,444.2
Accumulated depreciation of property and equipment	1,248.6	1,278.5
Property and equipment, net	1,366.6	1,165.7
Depreciation Expense	80.5	86.7	$ 86.0
Property and equipment subject to capital leases	0.1	4.9
Capitalized interest	18.7	7.5	2.1
Net of accumulated depreciation	0.7	3.8
Amortization expenses	0.5	1.5	$ 1.2
Vessels
Property and equipment
Cost	1,489.2	1,433.6
Accumulated depreciation of property and equipment	847.1	893.2
Property and equipment, net	642.1	540.4
Cost of completed vessel transferred from construction in progress	233.0
Capitalized interest	$ 12.8
Number of vesels under agreements for contstruction | item	4
Containers and equipment
Property and equipment
Cost	$ 513.6	543.0
Accumulated depreciation of property and equipment	362.9	349.0
Property and equipment, net	150.7	194.0
Terminal facilities and other property
Property and equipment
Cost	66.0	64.8
Accumulated depreciation of property and equipment	38.6	36.3
Property and equipment, net	27.4	28.5
Vessel construction in progress
Property and equipment
Cost	487.2	376.6
Property and equipment, net	487.2	376.6
Capitalized interest	16.3	10.4
Other construction in progress
Property and equipment
Cost	59.2	26.2
Property and equipment, net	$ 59.2	$ 26.2