Summary of Significant Accounting Policies (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Cash Equivalents and Short-term Investments [Abstract]
Short-term investments	$ 18,494	$ 16,707
Trade Accounts Receivable [Abstract]
Past due threshold for individual collectability review (in days)	90D
Buildings [Member]
Property, Plant and Equipment [Abstract]
Annual rates of depreciation, minimum (in hundredths)	3.00%
Annual rates of depreciation, maximum (in hundredths)	6.67%
Machinery and equipment [Member]
Property, Plant and Equipment [Abstract]
Annual rates of depreciation, minimum (in hundredths)	6.67%
Annual rates of depreciation, maximum (in hundredths)	12.50%
Furniture and fixtures [Member]
Property, Plant and Equipment [Abstract]
Annual rates of depreciation, minimum (in hundredths)	8.00%
Annual rates of depreciation, maximum (in hundredths)	12.50%
Computer equipment and software-related assets [Member]
Property, Plant and Equipment [Abstract]
Annual rates of depreciation, minimum (in hundredths)	12.50%
Annual rates of depreciation, maximum (in hundredths)	25.00%
PCC production facilities [Member]
Property, Plant and Equipment [Abstract]
Estimated useful life (in years)	15
Initial term of long term evergreen contracts (in years)	10Y
Machinery and equipment for natural stone mining and processing plants and chemical plants [Member]
Property, Plant and Equipment [Abstract]
Estimated useful life (in years)	15