Summary of Significant Accounting Policies,Textuals, Property, Plant and Equipment (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Property, Plant and Equipment
Interest expense capitalized as construction in progress	$ 0.5	$ 0.2	$ 1.1	$ 0.4
Depreciation expense			12.0	11.6
Fabricated Products
Property, Plant and Equipment
Depreciation expense	$ 6.0	$ 5.7	$ 11.8	$ 11.4