Properties and Equipment (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Property, Plant and Equipment [Line Items]
Adjustments to retire property plant and equipment	$ 10.3	$ 9.1
Accumulated depreciation associated with retirement of property plant and equipment	9.8	7.9
Loss associated with disposal of property plant and equipment	0.5	1.2
Software and Software Development Costs [Member]
Property, Plant and Equipment [Line Items]
Capitalized computer software costs	$ 0.2	$ 1.1