CONSOLIDATED STATEMENTS OF INCOME AND COMPREHENSIVE INCOME (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Operating Revenue:
Ocean transportation	$ 1,189.8	$ 1,076.2	$ 1,015.0
Logistics	370.2	386.4	355.6
Total operating revenue	1,560.0	1,462.6	1,370.6
Costs and Expenses:
Operating costs	1,338.1	1,280.1	1,144.7
Equity in income of terminal joint venture	(3.2)	(8.6)	(12.8)
Selling, general and administrative	119.8	112.5	113.3
Separation costs	8.6
Operating costs and expenses	1,463.3	1,384.0	1,245.2
Operating Income	96.7	78.6	125.4
Interest expense	(11.7)	(7.7)	(8.2)
Income from Continuing Operations Before Income Taxes	85.0	70.9	117.2
Income tax expense	33.0	25.1	46.7
Income From Continuing Operations	52.0	45.8	70.5
Income (Loss) From Discontinued Operations (net of income taxes)	(6.1)	(11.6)	21.6
Net Income	45.9	34.2	92.1
Other Comprehensive Income, Net of Tax:
Net Income	45.9	34.2	92.1
Defined benefit pension plans:
Net loss and prior service cost	(4.6)	(5.7)	(7.0)
Amortization of prior service cost included in net periodic pension cost	(1.4)	0.3	0.2
Amortization of net loss included in net periodic pension cost	4.8	3.9	2.1
Other Comprehensive income from Discontinued Operations	0.7	(8.4)	3.7
Other Comprehensive Income	(0.5)	(9.9)	(1.0)
Comprehensive Income	$ 45.4	$ 24.3	$ 91.1
Basic Earnings (Loss) Per Share:
Continuing operations (in dollars per share)	$ 1.23	$ 1.10	$ 1.71
Discontinued operations (in dollars per share)	$ (0.14)	$ (0.28)	$ 0.52
Net income (in dollars per share)	$ 1.09	$ 0.82	$ 2.23
Diluted Earnings (Loss) Per Share:
Continuing operations (in dollars per share)	$ 1.22	$ 1.09	$ 1.70
Discontinued operations (in dollars per share)	$ (0.14)	$ (0.28)	$ 0.52
Net income (in dollars per share)	$ 1.08	$ 0.81	$ 2.22
Weighted Average Number of Shares Outstanding:
Basic (in shares)	42.3	41.6	41.2
Diluted (in shares)	42.7	42.0	41.5
Cash Dividends Per Share (in dollars per share)	$ 0.93	$ 1.26	$ 1.26