Fair Value (Summary of Assets And Liabilities Measured at Fair Value) (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 24, 2017
Fair Value, Measurements, Recurring
Assets:
Cash equivalents	$ 687,956	$ 488,432	$ 425,000
Marketable securities	59,843	48,006	45,726
Derivatives	12,531	1,769	724
Assets, fair value	760,330	538,207	471,450
Liabilities:
Derivatives, liabilities	931	21,308	32,414
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Cash equivalents	446,300	358,500	425,000
Marketable securities	49,832	48,006	45,726
Derivatives	0	0	0
Assets, fair value	496,132	406,506	470,726
Liabilities:
Derivatives, liabilities	0	0	0
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Cash equivalents	241,656	129,932	0
Marketable securities	10,011	0	0
Derivatives	12,531	1,769	724
Assets, fair value	264,198	131,701	724
Liabilities:
Derivatives, liabilities	931	21,308	32,414
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents	0	0	0
Marketable securities	0	0	0
Derivatives	0	0	0
Assets, fair value	0	0	0
Liabilities:
Derivatives, liabilities	0	0	0
Fair Value, Measurements, Nonrecurring | Fair Value Adjustment
Liabilities:
Repossessed inventory	6,700	9,000	9,000
Fair Value, Measurements, Nonrecurring | Significant Other Observable Inputs (Level 2) | Fair Value
Liabilities:
Repossessed inventory	$ 19,500	$ 19,600	$ 21,300