Financial Instruments And Risk Management (Gross Notional Amount Of Outstanding Derivative Instruments) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative, Remaining Maturity	4 years
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	$ 353,975	$ 399,348	$ 493,828
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	$ 359,179	$ 379,701	$ 419,707