Condensed Consolidated Statements of Income and Comprehensive Income - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Operating Revenue:
Ocean Transportation	$ 346.7	$ 321.1	$ 652.2	$ 615.7
Logistics	100.9	115.3	193.6	213.2
Total Operating Revenue	447.6	436.4	845.8	828.9
Costs and Expenses:
Operating costs	364.5	366.9	682.7	714.7
Equity in income of terminal joint venture	(5.2)	(2.1)	(8.6)	(2.3)
Selling, general and administrative	54.6	35.9	93.1	70.9
Total Costs and Expenses	413.9	400.7	767.2	783.3
Operating Income	33.7	35.7	78.6	45.6
Interest expense	(4.6)	(4.5)	(8.9)	(8.6)
Income before Income Taxes	29.1	31.2	69.7	37.0
Income tax expense	(19.2)	(13.1)	(34.8)	(15.5)
Net Income	9.9	18.1	34.9	21.5
Other Comprehensive Income (Loss), Net of Income Taxes:
Net Income	9.9	18.1	34.9	21.5
Other Comprehensive Income (Loss):
Net loss in prior service cost			(0.2)
Amortization of prior service cost included in net periodic pension cost	(0.2)	(0.2)	(0.6)	(0.5)
Amortization of net gain included in net periodic pension cost	0.9	0.7	2.3	1.4
Foreign currency translation adjustment	0.6		0.7	(0.1)
Total Other Comprehensive Income	1.3	0.5	2.2	0.8
Comprehensive Income	$ 11.2	$ 18.6	$ 37.1	$ 22.3
Basic Earnings Per Share:
Basic Earnings Per Share (in dollars per share)	$ 0.23	$ 0.42	$ 0.80	$ 0.50
Diluted Earnings Per Share:
Diluted Earnings Per Share (in dollars per share)	$ 0.23	$ 0.42	$ 0.79	$ 0.50
Weighted Average Number of Shares Outstanding:
Basic (in shares)	43.5	43.0	43.4	43.0
Diluted (in shares)	44.0	43.2	43.9	43.2
Dividends:
Cash Dividends Per Share (in dollars per share)	$ 0.17	$ 0.16	$ 0.34	$ 0.32