Fair Value Measurements (Narrative) (Details) (USD $)	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Number of years long-term sales growth forecasted over	5 years
Average long-term sales growth forecast, over next 5 years, percent per year	40.00%
Derivative instrument	7,100,000
Percentage of anticipated aluminum purchases in 2012	20.00%
Number of pounds settled at loss	2,500,000
Amount settled at loss	$ 300,000
Number of vacant owned facilities classified in fixed assets	5
Number of vacant owned facilities sold at carrying value	2
Average mid-west aluminum price per pound	1.02
Vacant Owned Facilities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Number of vacant facilities owned	8
Number of vacant facilities owned that did not exceed their carrying value	3
Impairment charge	500,000
Estimated combined fair value	5,800,000
Number of owned facilities leased to third parties	2
Leased facilities combined carrying value	3,800,000
Lease term period, maximum	5 years
Annual rental income	400,000
Other Indentifiable Intangible Assets [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Non-cash impairment charge	1,200,000
Vacant Leased Facilities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Charge due to early termination of leases of vacant facilities	100,000	200,000
Cost of Sales [Member] | Other Indentifiable Intangible Assets [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Non-cash impairment charge	$ 1,000,000