Condensed Consolidated Statements of Income and Comprehensive Income (Unaudited) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Operating Revenue:
Ocean transportation	$ 299.5	$ 274.3	$ 579.0	$ 512.7
Logistic services	94.7	103.1	181.3	194.4
Total operating revenue	394.2	377.4	760.3	707.1
Costs and Expenses:
Operating costs	329.0	323.0	659.0	619.1
Equity in income of terminal joint venture	(1.6)	(2.8)	(2.4)	(4.0)
Selling, general and administrative	28.5	28.0	56.8	56.1
Separation costs	5.8		8.3
Operating costs and expenses	361.7	348.2	721.7	671.2
Operating Income	32.5	29.2	38.6	35.9
Interest expense	(1.9)	(1.9)	(3.9)	(3.8)
Income from Continuing Operations Before Income Taxes	30.6	27.3	34.7	32.1
Income tax expense	15.3	9.6	17.4	11.4
Income From Continuing Operations	15.3	17.7	17.3	20.7
Income (Loss) From Discontinued Operations (net of income taxes)	(7.5)	1.0	(6.1)	3.2
Net Income	7.8	18.7	11.2	23.9
Other Comprehensive Income, Net of Tax:
Net Income	7.8	18.7	11.2	23.9
Defined benefit pension plans:
Less: amortization of prior service cost included in net periodic pension cost	(0.2)	0.1	(0.3)	0.1
Less: amortization of net loss included in net periodic pension cost	(0.2)	0.1	0.9	0.8
Other Comprehensive Income	(0.4)	0.2	0.6	0.9
Comprehensive Income	$ 7.4	$ 18.9	$ 11.8	$ 24.8
Basic Earnings Per Share:
Continuing operations (in dollars per share)	$ 0.36	$ 0.42	$ 0.41	$ 0.50
Discontinued operations (in dollars per share)	$ (0.18)	$ 0.03	$ (0.14)	$ 0.07
Net income (in dollars per share)	$ 0.18	$ 0.45	$ 0.27	$ 0.57
Diluted Earnings Per Share:
Continuing operations (in dollars per share)	$ 0.36	$ 0.42	$ 0.41	$ 0.50
Discontinued operations (in dollars per share)	$ (0.18)	$ 0.02	$ (0.15)	$ 0.07
Net income (in dollars per share)	$ 0.18	$ 0.44	$ 0.26	$ 0.57
Weighted Average Number of Shares Outstanding:
Basic (in shares)	42.3	41.7	42.1	41.6
Diluted (in shares)	42.8	42.2	42.5	42.0
Cash Dividends Per Share (in dollars per share)	$ 0.315	$ 0.315	$ 0.63	$ 0.63