Fair Value Measurements (Summary Of Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Estimate of Fair Value Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	$ 759,984	$ 722,209
Marketable securities	43,638	81,448
Derivatives	29,034	16,235
Derivatives	142	1,300
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	531,519	555,910
Marketable securities	43,638	81,448
Derivatives	29,034	16,235
Total	604,191	653,593
Derivatives	142	1,300
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	426,266	390,706
Marketable securities	38,119	36,256
Derivatives	0	0
Total	464,385	426,962
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	105,253	165,204
Marketable securities	5,519	45,192
Derivatives	29,034	16,235
Total	139,806	226,631
Derivatives	142	1,300
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	9,300	8,600
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	$ 19,300	$ 17,700