Goodwill and Other Intangible Assets (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Schedule of goodwill
Beginning Balance, Goodwill				$ 18.1	$ 18.1	$ 18.1
Beginning Balance, Accumulated Impairments				(9.9)	(9.5)	(9.5)
Beginning Balance, Goodwill Net				8.2	8.6	8.6
Goodwill
Goodwill impairment	(1.9)	(0.1)	(0.3)	(1.9)	(0.4)
Goodwill, Net				(1.9)	(0.4)
Ending Balance, Goodwill	18.1	18.1		18.1	18.1	18.1
Ending Balance, Accumulated Impairments	(11.8)	(9.9)		(11.8)	(9.9)	(9.5)
Ending Balance, Goodwill Net	6.3	8.2		6.3	8.2	8.6
Customer relationships [Member]
Summary of Goodwill and Other Intangible Assets
Cost amortizable intangible assets	1.4	1.4		1.4	1.4
Accumulated amortization intangible assets	$ 0.6	$ 0.5		$ 0.6	$ 0.5