INVESTMENT IN SSAT (Details) - USD ($) $ in Millions		12 Months Ended
	Jan. 01, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Investments in affiliates
Investment in Terminal Joint Venture		$ 76.2	$ 87.0
Financial information for equity method investment
Income from SSAT		20.8	36.8	$ 28.2
Distributions Received		25.2	42.0	17.5
Operating lease right of use assets		256.1
Long-term operating lease liabilities		198.0
ASU 2016-02 New Lease Accounting Standard
Financial information for equity method investment
Cumulative-effect adjustment recorded to retained earnings	$ (4.4)	$ (4.4)
Operating lease right of use assets	$ 251.4
Ocean Transportation | SSAT
Investments in affiliates
Ownership interest accounted in the related party terminal joint venture (as a percent)		35.00%
Cost of services from transactions with unconsolidated affiliate		$ 218.7	213.4	181.3
Accounts payable and accrued liabilities		63.6	59.2
Financial information for equity method investment
Income from SSAT		20.8	36.8	28.2
Cumulative-effect adjustment recorded to retained earnings		5.6
Current assets		300.8	310.4
Noncurrent assets		1,283.0	152.1
Total assets		1,583.8	462.5
Current liabilities		201.9	71.0
Noncurrent liabilities		1,179.2	156.2
Equity		202.7	235.3
Total Liabilities and Equity		1,583.8	462.5
Operating revenue		1,098.3	1,074.2	933.5
Operating costs and expenses		1,035.3	963.7	850.2
Operating Income		63.0	110.5	83.3
Net Income		57.2	$ 104.9	$ 80.9
Operating lease right of use assets		1,117.0
Operating lease liabilities		135.7
Long-term operating lease liabilities		$ 1,033.1