Goodwill and Intangible Assets, Identifiable Intangible Table (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2012
Identifiable intangible assets
Weighted average estimated useful life	24 years
Original cost	$ 39.7	$ 39.7
Accumulated amortization	(2.5)	(4.3)
Total	37.2	35.4
Customer relationships
Identifiable intangible assets
Weighted average estimated useful life	25 years
Original cost	38.5	38.5
Accumulated amortization	(1.7)	(3.2)
Total	36.8	35.3
Backlog
Identifiable intangible assets
Weighted average estimated useful life	2 years
Original cost	0.8	0.8
Accumulated amortization	(0.7)	(0.8)
Total	0.1	0
Trademark and trade name
Identifiable intangible assets
Weighted average estimated useful life	3 years
Original cost	0.4	0.4
Accumulated amortization	(0.1)	(0.3)
Total	$ 0.3	$ 0.1