Fair Value Measurements (Summary Of Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) (Fair Value, Measurements, Recurring [Member], USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Estimate of Fair Value Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	$ 836,387	$ 834,562
Marketable securities	129,181	154,051
Derivatives	1,932	317
Assets, Fair Value Disclosure	967,500	988,930
Derivatives, Liabilities	3,925	7,920
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	516,173	672,274
Marketable securities	30,172	18,417
Derivatives	0	0
Assets, Fair Value Disclosure	546,345	690,691
Derivatives, Liabilities	0	0
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	320,214	162,288
Marketable securities	99,009	135,634
Derivatives	1,932	317
Assets, Fair Value Disclosure	421,155	298,239
Derivatives, Liabilities	3,925	7,920
Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Marketable securities	0	0
Derivatives	0	0
Assets, Fair Value Disclosure	0	0
Derivatives, Liabilities	$ 0	$ 0