Changes in Operations (Details 2)	12 Months Ended			1 Months Ended	12 Months Ended										1 Months Ended
	Dec. 31, 2011 USD ($)	Dec. 31, 2010 USD ($)	Dec. 31, 2009 USD ($)	Dec. 31, 2010 FreightLink [Member] USD ($)	Dec. 31, 2011 FreightLink [Member] USD ($)	Dec. 31, 2009 FreightLink [Member] USD ($)	Dec. 01, 2010 FreightLink [Member] USD ($)	Dec. 01, 2010 FreightLink [Member] AUD	Sep. 30, 2010 FreightLink [Member] USD ($)	Jun. 30, 2010 FreightLink [Member] USD ($)	Mar. 31, 2010 FreightLink [Member] USD ($)	Sep. 30, 2009 FreightLink [Member] USD ($)	Jun. 30, 2009 FreightLink [Member] USD ($)	Mar. 31, 2009 FreightLink [Member] USD ($)	Dec. 31, 2010 United States Revolving Loan [Member] FreightLink [Member] USD ($)	Dec. 31, 2010 Australia Revolving Loan [Member] FreightLink [Member] USD ($)	Dec. 31, 2010 Australia Revolving Loan [Member] FreightLink [Member] AUD
Business Acquisition [Line Items]
Cost of acquired entity							$ 320,000,000	331,900,000
Long-term debt assumed					2,000,000		1,741,000	1,806,000
Non-interest bearing note	676,136,000				51,000,000		48,200,000	50,000,000
Debt instrument, maturity date	Jul. 29, 2016				Jan. 14, 2054
Concession Agreement expiration date					Jan. 14, 2054
Business acquisition revenue to be eliminated					33,900,000
Foreign currency exchange rate used to translate balance sheet				0.99		0.91	0.96		0.91	0.88	0.90	0.83	0.76	0.66
Acquisition costs				28,200,000		7,800,000
Stamp duty	0	16,369,000	0	16,400,000
Other expenses				11,000,000
Labor and benefits	236,152,000	207,736,000	191,479,000	800,000
Proceeds from long-term lines of credit															$ 100,000,000	$ 94,000,000	97,000,000