Derivative Instruments (Fair Value Of Outstanding Derivative Contracts Recorded As Liabilities) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Derivatives, Fair Value [Line Items]
Total liability derivatives	$ 1,970	$ 2,453
Derivatives Designated As Hedging Instruments Under ASC 815 [Member]
Derivatives, Fair Value [Line Items]
Total liability derivatives	1,830	2,394
Derivatives Designated As Hedging Instruments Under ASC 815 [Member] | Accounts Payable And Accrued Liabilities [Member] | Foreign Exchange Contracts [Member]
Derivatives, Fair Value [Line Items]
Total liability derivatives	309	243
Derivatives Designated As Hedging Instruments Under ASC 815 [Member] | Accounts Payable And Accrued Liabilities [Member] | Natural Gas Contracts [Member]
Derivatives, Fair Value [Line Items]
Total liability derivatives	1,286	1,608
Derivatives Designated As Hedging Instruments Under ASC 815 [Member] | Accrued Pension And Other Liabilities [Member] | Foreign Exchange Contracts [Member]
Derivatives, Fair Value [Line Items]
Total liability derivatives	26	34
Derivatives Designated As Hedging Instruments Under ASC 815 [Member] | Accrued Pension And Other Liabilities [Member] | Natural Gas Contracts [Member]
Derivatives, Fair Value [Line Items]
Total liability derivatives	209	509
Derivatives Not Designated As Hedging Instruments Under ASC 815 [Member] | Accounts Payable And Accrued Liabilities [Member] | Foreign Exchange Contracts [Member]
Derivatives, Fair Value [Line Items]
Total liability derivatives	$ 140	$ 59