Consolidated Statements of Income and Comprehensive Income - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating Revenue:
Total Operating Revenue	$ 2,222.8	$ 2,046.9	$ 1,941.6
Costs and Expenses:
Operating costs	(1,875.0)	(1,721.0)	(1,617.6)
Equity in income of Terminal Joint Venture	36.8	28.2	15.8
Selling, general and administrative	(220.8)	(206.8)	(183.1)
Total Costs and Expenses	(2,059.0)	(1,899.6)	(1,784.9)
Operating Income	163.8	147.3	156.7
Interest expense	(18.7)	(24.2)	(24.1)
Other income (expense), net	2.6	2.1	(2.1)
Income before Income Taxes	147.7	125.2	130.5
Income taxes	(38.7)	105.8	(49.1)
Net Income	109.0	231.0	81.4
Other Comprehensive Income (Loss), Net of Income Taxes:
Net Income	109.0	231.0	81.4
Other Comprehensive Income (Loss):
Net gain in prior service cost		0.8	24.1
Amortization of prior service cost	(4.7)	(4.0)	(2.2)
Amortization of net loss	1.1	1.7	1.2
Other adjustments		0.2	0.2
Total Other Comprehensive Income (Loss)	(3.6)	(1.3)	23.3
Comprehensive Income	$ 105.4	$ 229.7	$ 104.7
Basic Earnings Per-Share: (in dollars per share)	$ 2.55	$ 5.38	$ 1.89
Diluted Earnings Per-Share: (in dollars per share)	$ 2.53	$ 5.35	$ 1.87
Weighted Average Number of Shares Outstanding:
Basic (in shares)	42.7	42.9	43.1
Diluted (in shares)	43.0	43.2	43.5
Ocean Transportation
Operating Revenue:
Total Operating Revenue	$ 1,641.3	$ 1,571.8	$ 1,541.1
Logistics
Operating Revenue:
Total Operating Revenue	$ 581.5	$ 475.1	$ 400.5