Derivatives And Risk Management Derivatives and Risk Management (Foreign Currency Exchange Contracts) (Details) CAD in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($) Caontracts	Dec. 31, 2015 CAD Caontracts	Dec. 31, 2014 USD ($) Caontracts	Dec. 31, 2014 CAD Caontracts
Schedule of Foreign Currency Derivative Contracts Outstanding [Line Items]
Number Of Days Canadian Currency Prices Are Settled With U.S. Dollars	60 days
Number of Foreign Currency Derivatives Held | Caontracts	24	24	18	18
Foreign Currency Exchange Contracts [Member] | United States of America, Dollars
Schedule of Foreign Currency Derivative Contracts Outstanding [Line Items]
Derivative, Notional Amount | $	$ 1,463		$ 5,474
Foreign Currency Exchange Contracts [Member] | Canada, Dollars
Schedule of Foreign Currency Derivative Contracts Outstanding [Line Items]
Derivative, Notional Amount | CAD		CAD 2,002		CAD 6,198