Fair Value Measurements (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Number of years long-term sales growth forecasted over	4 years
Average long-term sales growth forecast, over next 4 years, percent per year	25.00%
Amount of aluminum owned through derivative instruments	4,700,000
Percentage of anticipated aluminum purchases in 2012	15.00%
Number of pounds settled at loss	4,900,000
Derivative asset recorded in prepaid expenses and other current assets	$ 200,000
Derivative liabilities recorded in accrued expenses and other current liabilities		400,000
Average mid-west aluminum price per pound	1.01
Vacant Owned Facilities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Number of vacant facilities owned	8
Number of vacant owned facilities that with carrying values exceeding fair value	5
Impairment charge	500,000		400,000
Gain on sale of facilities	800,000
Estimated combined fair value	5,000,000
Number of vacant owned facilities classified in fixed assets	4
Number of owned facilities leased to third parties	2
Number of vacant owned facilities sold at carrying value	2
Leased facilities combined carrying value	3,800,000		11,600,000
Lease term period, maximum	5 years
Annual rental income	300,000
Other Indentifiable Intangible Assets [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other intangible assets, carrying value	1,200,000
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	100,000
Cost of Sales [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amount settled at loss	400,000
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