Condensed Consolidated Statements of Income and Comprehensive Income (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Operating Revenue:
Ocean transportation	$ 321.1	$ 310.0	$ 615.7	$ 609.9
Logistics	115.3	106.6	213.2	201.4
Total operating revenue	436.4	416.6	828.9	811.3
Costs and Expenses:
Operating costs	366.9	344.9	714.7	687.7
Equity in (income) loss of terminal joint venture	(2.1)	0.8	(2.3)	0.6
Selling, general and administrative	35.9	34.4	70.9	67.8
Total costs and expenses	400.7	380.1	783.3	756.1
Operating Income	35.7	36.5	45.6	55.2
Interest expense	(4.5)	(3.6)	(8.6)	(7.3)
Income before income taxes	31.2	32.9	37.0	47.9
Income tax expense	(13.1)	(12.8)	(15.5)	(18.7)
Net Income	18.1	20.1	21.5	29.2
Other Comprehensive Income (Loss), Net of Income Taxes:
Net Income	18.1	20.1	21.5	29.2
Other Comprehensive Income (Loss):
Net gain (loss) and prior service cost	0	(0.8)	0	(0.8)
Amortization of prior service cost included in net periodic pension cost	(0.2)	(0.4)	(0.5)	(0.7)
Amortization of net loss included in net periodic pension cost	0.7	0.9	1.4	2.3
Foreign currency translation adjustment	0	(0.4)	(0.1)	(0.2)
Total Other Comprehensive Income (Loss)	0.5	(0.7)	0.8	0.6
Comprehensive Income	$ 18.6	$ 19.4	$ 22.3	$ 29.8
Basic Earnings Per Share (in dollars per share)	$ 0.42	$ 0.47	$ 0.50	$ 0.68
Diluted Earnings Per Share (in dollars per share)	$ 0.42	$ 0.47	$ 0.50	$ 0.68
Weighted Average Number of Shares Outstanding:
Basic (in shares)	43.0	42.7	43.0	42.7
Diluted (in shares)	43.2	43.0	43.2	43.0