Fair Value Measurements (Summary Of Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	$ 998,601	$ 488,432
Marketable securities	54,250	48,006
Derivatives	15,071	1,769
Total	1,067,922	538,207
Derivatives	5,316	21,308
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	728,800	358,500
Marketable securities	44,243	48,006
Derivatives	0	0
Total	773,043	406,506
Derivatives	0	0
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	269,801	129,932
Marketable securities	10,007	0
Derivatives	15,071	1,769
Total	294,879	131,701
Derivatives	5,316	21,308
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Marketable securities	0	0
Derivatives	0	0
Total	0	0
Derivatives	0	0
Fair Value, Measurements, Nonrecurring | Fair Value Adjustment
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Repossessed inventory at the lower of cost or net realizable value	9,700	9,000
Fair Value, Measurements, Nonrecurring | Significant Other Observable Inputs (Level 2) | Estimate of Fair Value Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Repossessed inventory at the lower of cost or net realizable value	$ 20,200	$ 19,600