Condensed Consolidated Balance Sheets (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Current Assets:
Cash and cash equivalents	$ 229.7	$ 114.5
Accounts receivable, net	177.9	182.3
Deferred income taxes	9.1	9.1
Prepaid expenses and other assets	40.5	43.0
Total current assets	457.2	348.9
Investment in terminal joint venture	57.8	57.6
Property and equipment, net	722.9	735.4
Goodwill and intangible assets, net	31.0	31.2
Other long-term assets	75.4	75.2
Total assets	1,344.3	1,248.3
Current Liabilities:
Current portion of long-term debt	12.5	12.5
Accounts payable	124.5	124.0
Payroll and vacation benefits	16.5	16.9
Self-insured liabilities	15.4	15.1
Accrued and other liabilities	30.4	32.1
Total current liabilities	199.3	200.6
Long-term Liabilities:
Long-term debt	371.1	273.6
Deferred income taxes	327.0	326.1
Employee benefit plans	74.3	74.4
Self-insured claims and other liabilities	36.7	35.4
Total long-term liabilities	809.1	709.5
Commitments and Contingencies (Note 6)
Shareholders' Equity:
Capital stock	32.1	32.1
Additional paid in capital	262.8	261.9
Accumulated other comprehensive loss	(23.2)	(23.5)
Retained earnings	64.2	67.7
Total shareholders' equity	335.9	338.2
Total liabilities and shareholders' equity	$ 1,344.3	$ 1,248.3