Property, Plant and Equipment (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2011 Y	Dec. 31, 2010
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 326,177	$ 280,655
Less accumulated depreciation and amortization	161,630	144,900
Property, plant and equipment, net	164,547	135,755
Machinery, equipment and automotive [Member]
Property, Plant and Equipment [Line Items]
Useful lives in years, Minimum	3
Useful lives in years, Maximum	30
Property, Plant and Equipment, Gross	239,322	217,539
Buildings and improvements [Member]
Property, Plant and Equipment [Line Items]
Useful lives in years, Minimum	7
Useful lives in years, Maximum	30
Property, Plant and Equipment, Gross	39,381	34,392
Furniture, fixtures and store equipment [Member]
Property, Plant and Equipment [Line Items]
Useful lives in years, Minimum	3
Useful lives in years, Maximum	10
Property, Plant and Equipment, Gross	5,926	5,952
Assets under capital leases [Member]
Property, Plant and Equipment [Line Items]
Useful lives in years, Average	10
Property, Plant and Equipment, Gross	2,105	2,415
Land improvements [Member]
Property, Plant and Equipment [Line Items]
Useful lives in years, Average	10
Property, Plant and Equipment, Gross	1,080	910
Construction in progress [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	23,714	9,549
Capital spare parts [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	7,407	5,577
Land [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 7,242	$ 4,321

The cumulative amount of depreciation, depletion and amortization (related to property, plant and equipment, but not including land) that has been recognized in the income statement.

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Gross amount, at the balance sheet date, of long-lived physical assets used in the normal conduct of business and not intended for resale. This can include land, buildings, machinery and equipment, and other types of furniture and equipment including, but not limited to, office equipment, furniture and fixtures, and computer equipment and software.

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- Definition

Tangible assets that are held by an entity for use in the production or supply of goods and services, for rental to others, or for administrative purposes and that are expected to provide economic benefit for more than one year; net of accumulated depreciation. Examples include land, buildings, machinery and equipment, and other types of furniture and equipment including, but not limited to, office equipment, furniture and fixtures, and computer equipment and software.

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