Fair Value Measurements (Assets And Liabilities Measured On Recurring Basis) (Details) $ in Thousands	Jun. 30, 2015 USD ($) item	Dec. 31, 2014 USD ($) item
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Total	$ 422,800	$ 471,193
Derivatives	12,356	16,151
Total Assets	301,365	337,746
Derivatives	(8,131)	(4,253)
Total Liabilities	$ (8,131)	$ (4,253)
Number of items measured at fair value on a nonrecurring basis | item	0	0
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Assets	$ 101,905	$ 127,344
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	12,356	16,151
Total Assets	199,460	210,402
Derivatives	(8,131)	(4,253)
Total Liabilities	(8,131)	(4,253)
Money Market Accounts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Total	98,993	124,432
Money Market Accounts [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Total	98,993	124,432
Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Total	117,804	113,076
Corporate Bonds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Total	117,804	113,076
U.S. Treasuries And Agencies Available For Sale Securities Portion [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Total	69,300	73,912
U.S. Treasuries And Agencies Available For Sale Securities Portion [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Total	69,300	73,912
Foreign Government Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Total		7,263
Foreign Government Bonds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Total		7,263
Time Deposits [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Total	2,912	2,912
Time deposits	2,912	2,912
Time Deposits [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Time deposits	$ 2,912	$ 2,912