Segment and Geographical Area Information (Details) (USD $) In Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010
Net Sales:
Total net sales	$ 338.8	$ 282.4	$ 661.4	$ 549.9
Segment Operating Income (Loss):
Total operating income (loss)	15.4	4.0	35.9	18.8
Interest expense	(4.4)	(3.5)	(8.9)	(3.5)
Other (expense) income, net	(3.4)	0.7	(1.7)	0.9
Income before income taxes	7.6	1.2	25.3	16.2
Depreciation and Amortization:
Depreciation and amortization	6.4	5.0	12.7	9.0
Capital expenditures:
Capital expenditures	7.9	12.8	14.1	26.7
Income Taxes Paid:
Income taxes paid			1.0	0.3
Segment assets:
Total assets	1,419.8		1,419.8		1,342.4
Fabricated Products [Member]
Net Sales:
Total net sales	338.8	282.4	661.4	549.6
Segment Operating Income (Loss):
Total operating income (loss)	32.9	32.2	56.6	54.3
Depreciation and Amortization:
Depreciation and amortization	6.3	4.9	12.4	8.9
Capital expenditures:
Capital expenditures	7.9	12.3	14.1	25.8
Income Taxes Paid:
Income taxes paid	0.9	0.2	1.0	0.3
Segment assets:
Total assets	625.3		625.3		496.7
Fabricated Products [Member] | United States [Member]
Income Taxes Paid:
Income taxes paid	0.7	0.2	0.8	0.2
Fabricated Products [Member] | Canada [Member]
Income Taxes Paid:
Income taxes paid	0.2		0.2	0.1
All Other [Member]
Net Sales:
Total net sales				0.3
Segment Operating Income (Loss):
Total operating income (loss)	(17.5)	(28.2)	(20.7)	(35.5)
Depreciation and Amortization:
Depreciation and amortization	0.1	0.1	0.3	0.1
Capital expenditures:
Capital expenditures		0.5		0.9
Segment assets:
Total assets	$ 794.5		$ 794.5		$ 845.7