Condensed Consolidated Statements of Income and Comprehensive Income - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Operating Revenue:
Total Operating Revenue	$ 880.1	$ 962.0	$ 2,492.6	$ 2,531.5
Costs and Expenses:
Operating costs	(661.1)	(654.3)	(1,942.6)	(1,913.4)
Income from SSAT	9.3	6.9	23.2	8.5
General and administrative	(67.3)	(72.3)	(217.1)	(222.8)
Total Costs and Expenses	(719.1)	(719.7)	(2,136.5)	(2,127.7)
Operating Income	161.0	242.3	356.1	403.8
Interest income	7.6	10.4	25.0	38.0
Interest expense	(1.8)	(1.8)	(5.2)	(6.1)
Other income (expense), net	2.1	1.9	6.9	5.5
Income before Taxes	168.9	252.8	382.8	441.2
Income taxes	(34.2)	(53.7)	(81.1)	(92.8)
Net Income	134.7	199.1	301.7	348.4
Comprehensive Income (Loss), Net of Income Taxes:
Net Income	134.7	199.1	301.7	348.4
Other Comprehensive Income (Loss):
Net change in pension and post-retirement liabilities	(0.7)	(0.8)	(2.4)	(2.3)
Other adjustments	(1.6)	1.0	0.3	0.5
Total Other Comprehensive Income (Loss), Net of Income Taxes	(2.3)	0.2	(2.1)	(1.8)
Total Comprehensive Income	$ 132.4	$ 199.3	$ 299.6	$ 346.6
Basic Earnings Per Share (in dollars per share)	$ 4.28	$ 5.98	$ 9.4	$ 10.28
Diluted Earnings Per Share (in dollars per share)	$ 4.24	$ 5.89	$ 9.28	$ 10.13
Weighted Average Number of Shares Outstanding:
Basic (in shares)	31.5	33.3	32.1	33.9
Diluted (in shares)	31.8	33.8	32.5	34.4
Ocean Transportation
Operating Revenue:
Total Operating Revenue	$ 718.3	$ 798.7	$ 2,031.3	$ 2,067.6
Logistics
Operating Revenue:
Total Operating Revenue	$ 161.8	$ 163.3	$ 461.3	$ 463.9