Financial Instruments And Risk Management (Gross Notional Amount Of Outstanding Derivative Instruments) (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015
Derivative Instruments Designated As Cash Flow Hedges [Member] | Currency Forward Contracts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Currency forward contracts	$ 228,500	$ 161,000	$ 106,500
Derivative Instruments Designated As Cash Flow Hedges [Member] | Foreign Exchange Option [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Currency forward contracts	0	0	7,000
Derivative Instruments Not Designated As Cash Flow Hedges [Member] | Currency Forward Contracts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Currency forward contracts	$ 60,785	$ 113,195	$ 75,000