PROPERTY AND EQUIPMENT - SUMMARY (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Property and equipment
Cost	$ 2,836.7	$ 2,615.2
Accumulated depreciation of property and equipment	1,238.6	1,248.6
Property and equipment, net	1,598.1	1,366.6
Depreciation Expense	86.3	80.5	$ 86.7
Property and equipment subject to capital leases		0.1
Property and equipment subject to capital leases	0.0
Accumulated depreciation		0.7
Depreciation expense		0.5	$ 1.5
Vessels
Property and equipment
Cost	1,653.5	1,489.2
Accumulated depreciation of property and equipment	818.5	847.1
Property and equipment, net	835.0	642.1
Containers and equipment
Property and equipment
Cost	544.5	513.6
Accumulated depreciation of property and equipment	378.8	362.9
Property and equipment, net	165.7	150.7
Terminal facilities and other property
Property and equipment
Cost	114.4	66.0
Accumulated depreciation of property and equipment	41.3	38.6
Property and equipment, net	73.1	27.4
Vessel construction in progress
Property and equipment
Cost	488.9	487.2
Property and equipment, net	488.9	487.2
Other construction in progress
Property and equipment
Cost	35.4	59.2
Property and equipment, net	$ 35.4	$ 59.2