PROPERTY AND EQUIPMENT - SUMMARY (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Property and equipment
Cost	$ 2,912.3	$ 2,836.7
Accumulated depreciation	1,222.4	1,238.6
Property and equipment, net	1,689.9	1,598.1
Depreciation Expense	97.1	86.3	$ 80.5
Vessels
Property and equipment
Cost	2,191.6	1,653.5
Accumulated depreciation	785.5	818.5
Property and equipment, net	1,406.1	835.0
Containers and equipment
Property and equipment
Cost	572.3	544.5
Accumulated depreciation	391.8	378.8
Property and equipment, net	180.5	165.7
Terminal facilities and other property
Property and equipment
Cost	119.8	114.4
Accumulated depreciation	45.1	41.3
Property and equipment, net	74.7	73.1
Vessel construction in progress
Property and equipment
Cost		488.9
Property and equipment, net		488.9
Other construction in progress
Property and equipment
Cost	28.6	35.4
Property and equipment, net	$ 28.6	$ 35.4

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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