Summary of Significant Accounting Policies,Textuals, Property, Plant and Equipment (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Property, Plant and Equipment
Interest expense capitalized as construction in progress	$ 1.7	$ 1.3	$ 2.8
Depreciation expense	24.7	23.0	19.5
Impairment charge	4.4	0	4.6
Fabricated Products
Property, Plant and Equipment
Depreciation expense	24.2	22.7	19.4
Fabricated Products | Idled equipment
Property, Plant and Equipment
Impairment charge	4.4		2.0
Fabricated Products | Restructuring
Property, Plant and Equipment
Impairment charge			0.7
Fabricated Products | Sale of Greenwood, South Carolina facility
Property, Plant and Equipment
Impairment charge			1.9
Fabricated Products | Sale of Greenwood, South Carolina facility | Idled equipment
Property, Plant and Equipment
Impairment charge			$ 3.9
Minimum | Land improvements
Property, Plant and Equipment
Property, plant and equipment useful lives (in years)	3 years
Minimum | Buildings and leasehold improvements
Property, Plant and Equipment
Property, plant and equipment useful lives (in years)	15 years
Minimum | Machinery and equipment
Property, Plant and Equipment
Property, plant and equipment useful lives (in years)	1 year
Minimum | Capital lease assets
Property, Plant and Equipment
Property, plant and equipment useful lives (in years)	3 years
Maximum | Land improvements
Property, Plant and Equipment
Property, plant and equipment useful lives (in years)	25 years
Maximum | Buildings and leasehold improvements
Property, Plant and Equipment
Property, plant and equipment useful lives (in years)	45 years
Maximum | Machinery and equipment
Property, Plant and Equipment
Property, plant and equipment useful lives (in years)	24 years
Maximum | Capital lease assets
Property, Plant and Equipment
Property, plant and equipment useful lives (in years)	5 years