Derivative Instruments (Details 1) (USD $) In Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Other Derivatives
Effect of mark to market valuation	$ (0.3)	$ 0	$ 0.2	$ (0.1)
Settlements	0.1	0	0.1	0
Total fuel hedges	(0.2)	0	0.3	(0.1)
Foreign exchange hedges		0.3	(0.6)	(0.3)
Interest Rate Locks, 2005 to 2006 [Member]
Interest rate hedges effect on interest expense - increase/(decrease)
Effect on interest expense - increase/(decrease)	(0.1)	(0.1)	(0.2)	(0.2)
Expected effect during next twelve months	(0.3)		(0.3)
Interest Rate Locks, 2006 to 2007 [Member]
Interest rate hedges effect on interest expense - increase/(decrease)
Effect on interest expense - increase/(decrease)	0.9	0.9	1.8	1.9
Expected effect during next twelve months	3.4		3.4
TILC warehouse [Member]
Interest rate hedges effect on interest expense - increase/(decrease)
Effect on interest expense - increase/(decrease)	0	0	0	0.4
Expected effect during next twelve months	0		0
TRIP warehouse [Member]
Interest rate hedges effect on interest expense - increase/(decrease)
Effect on interest expense - increase/(decrease)	6.8	7.3	14.1	14.8
Expected effect during next twelve months	6.3		6.3
Debt Issuances, 2008 [Member]
Interest rate hedges effect on interest expense - increase/(decrease)
Effect on interest expense - increase/(decrease)	5.2	5.5	9.7	10.7
Expected effect during next twelve months	$ 18.2		$ 18.2