Derivative Financial Instruments (Schedule Of Contracts Designated As Hedged Instruments) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Norwegian Kroners [Member]
Foreign Exchange Contracts [Line Items]
Foreign exchange contracts, Notional Amount	$ 7,131	$ 3,633
Derivative, Maturity Date	Feb. 01, 2014	Sep. 01, 2012
British Pounds [Member]
Foreign Exchange Contracts [Line Items]
Foreign exchange contracts, Notional Amount	1,452	1,632
Derivative, Maturity Date	Feb. 01, 2014	Feb. 01, 2013
Euros [Member]
Foreign Exchange Contracts [Line Items]
Foreign exchange contracts, Notional Amount	17,186	14,937
Derivative, Maturity Date	Feb. 01, 2014	Feb. 01, 2013
Swiss Francs [Member]
Foreign Exchange Contracts [Line Items]
Foreign exchange contracts, Notional Amount	23,838	24,225
Derivative, Maturity Date	Feb. 01, 2014	Feb. 01, 2013
Canadian Dollars [Member]
Foreign Exchange Contracts [Line Items]
Foreign exchange contracts, Notional Amount	$ 10,499	$ 9,141
Derivative, Maturity Date	Feb. 01, 2014	Mar. 01, 2013