Derivatives And Risk Management (Foreign Currency Exchange Contracts) (Details) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011 USD ($)	Dec. 31, 2011 CAD	Dec. 31, 2010 USD ($)	Dec. 31, 2010 CAD
Derivatives And Risk Management [Abstract]
Number of days Canadian currency prices are settled with U.S. dollars	60	60
Number of contracts	28	28	29	29
Notional amount	$ 7,033	7,192	$ 10,916	10,989
Derivatives in other current assets	$ 32		$ 116