Condensed Consolidated Statements of Income and Comprehensive Income (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Operating Revenue:
Ocean transportation	$ 307.1	$ 281.4	$ 886.1	$ 794.1
Logistics	94.3	99.2	275.6	293.6
Total operating revenue	401.4	380.6	1,161.7	1,087.7
Costs and Expenses:
Operating costs	337.0	324.7	996.0	943.9
Equity in income of terminal joint venture	(0.7)	(2.8)	(3.1)	(6.8)
Selling, general and administrative	30.6	27.8	87.4	83.8
Separation costs	0.3		8.6
Operating costs and expenses	367.2	349.7	1,088.9	1,020.9
Operating Income	34.2	30.9	72.8	66.8
Interest expense	(4.0)	(1.9)	(7.9)	(5.7)
Income from Continuing Operations Before Income Taxes	30.2	29.0	64.9	61.1
Income tax expense	11.2	10.6	28.6	22.0
Income From Continuing Operations	19.0	18.4	36.3	39.1
Income (Loss) From Discontinued Operations (net of income taxes)	0.1	(9.7)	(6.0)	(6.5)
Net Income	19.1	8.7	30.3	32.6
Other Comprehensive Income, Net of Tax:
Net Income	19.1	8.7	30.3	32.6
Defined benefit pension plans:
Net loss and prior service cost			1.1	1.2
Less: amortization of prior service cost included in net periodic pension cost	0.7	(0.3)	1.0	(0.3)
Less: amortization of net loss included in net periodic pension cost	(2.7)	(2.5)	(3.5)	(2.8)
Other Comprehensive Income	(2.0)	(2.8)	(1.4)	(1.9)
Comprehensive Income	$ 17.1	$ 5.9	$ 28.9	$ 30.7
Basic Earnings (Loss) Per Share:
Continuing operations (in dollars per share)	$ 0.45	$ 0.44	$ 0.86	$ 0.94
Discontinued operations (in dollars per share)		$ (0.23)	$ (0.14)	$ (0.16)
Net income (in dollars per share)	$ 0.45	$ 0.21	$ 0.72	$ 0.78
Diluted Earnings (Loss) Per Share:
Continuing operations (in dollars per share)	$ 0.45	$ 0.44	$ 0.85	$ 0.94
Discontinued operations (in dollars per share)		$ (0.23)	$ (0.14)	$ (0.17)
Net income (in dollars per share)	$ 0.45	$ 0.21	$ 0.71	$ 0.77
Weighted Average Number of Shares Outstanding:
Basic (in shares)	42.5	41.7	42.2	41.6
Diluted (in shares)	42.8	42.1	42.6	42.0
Cash Dividends Per Share (in dollars per share)	$ 0.15	$ 0.315	$ 0.78	$ 0.945