INVESTMENT IN SSAT (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Sep. 16, 2022
Investments in affiliates
Investment in SSAT	$ 85.5	$ 81.2
Financial information for equity method investment
Company's share of net income	2.2	83.1	$ 56.3
Distributions Received		47.3	46.9
Total Current assets	602.3	759.6
Total Non-current assets	3,692.3	3,570.4
Total Assets	4,294.6	4,330.0
Total Current liabilities	562.3	581.6
Total Non-current liabilities	1,331.6	1,451.5
Total Liabilities and Shareholders' Equity	4,294.6	4,330.0
SSAT Terminals Oakland | SSAT
Investments in affiliates
Investment in SSAT, interest acquired (as a percent)				20.00%
SSAT
Investments in affiliates
Equity method investment decrease in investment in subsidiary	15.5
Equity method investment decrease in deferred tax assets in subsidiary	3.9
Equity method investment decrease in retained earnings in subsidiary	11.6
Ocean Transportation | SSAT
Financial information for equity method investment
Total Current assets	304.0	324.7
Total Non-current assets	1,510.2	1,436.0
Total Assets	1,814.2	1,760.7
Total Current liabilities	271.8	342.1
Total Non-current liabilities	1,255.3	1,199.5
Equity	287.1	219.1
Total Liabilities and Shareholders' Equity	1,814.2	1,760.7
Operating revenue	1,025.1	1,466.9	1,297.5
Operating costs and expenses	1,019.6	1,168.8	1,113.8
Operating (loss) income	5.5	298.1	183.7
Net Income	$ 11.9	249.6	161.7
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	$ 297.2	308.3	284.9
Accounts payable and accrued liabilities	43.4	43.6
Financial information for equity method investment
Company's share of net income	$ 2.2	$ 83.1	$ 56.3