Derivative Financial Instruments (Schedule Of Contracts Designated As Hedged Instruments) (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2013	Dec. 31, 2012
Norwegian Kroners [Member]
Foreign Exchange Contracts [Line Items]
Foreign exchange contracts, Notional Amount	$ 5,113	$ 7,131
Derivative, Maturity Date	Feb. 01, 2014	Feb. 01, 2014
British Pounds [Member]
Foreign Exchange Contracts [Line Items]
Foreign exchange contracts, Notional Amount	932	1,452
Derivative, Maturity Date	Feb. 01, 2014	Feb. 01, 2014
Euros [Member]
Foreign Exchange Contracts [Line Items]
Foreign exchange contracts, Notional Amount	10,365	17,186
Derivative, Maturity Date	Feb. 01, 2014	Feb. 01, 2014
Swiss Francs [Member]
Foreign Exchange Contracts [Line Items]
Foreign exchange contracts, Notional Amount	14,582	23,838
Derivative, Maturity Date	Feb. 01, 2014	Feb. 01, 2014
Canadian Dollars [Member]
Foreign Exchange Contracts [Line Items]
Foreign exchange contracts, Notional Amount	6,295	10,499
Derivative, Maturity Date	Feb. 01, 2014	Feb. 01, 2014
Japanese Yen [Member]
Foreign Exchange Contracts [Line Items]
Foreign exchange contracts, Notional Amount	$ 1,000,526
Derivative, Maturity Date	Feb. 01, 2015