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, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Property, Plant and Equipment
Interest expense capitalized as construction in progress	$ 0.7	$ 0.5	$ 1.1	$ 1.1
Depreciation expense			13.1	12.0
Fabricated Products
Property, Plant and Equipment
Depreciation expense	$ 6.5	$ 6.0	$ 13.0	$ 11.8