Fair Value (Summary of Assets And Liabilities Measured at Fair Value) (Detail) - USD ($) $ in Thousands	Apr. 01, 2018	Dec. 31, 2017	Mar. 26, 2017
Fair Value, Measurements, Recurring
Assets:
Cash equivalents	$ 653,124	$ 488,432	$ 628,895
Marketable securities	49,402	48,006	46,678
Derivatives	3,613	1,769	12,446
Assets, fair value	706,139	538,207	688,019
Liabilities:
Derivatives, liabilities	22,850	21,308	1,052
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Cash equivalents	326,324	358,500	370,084
Marketable securities	49,402	48,006	41,674
Derivatives	0	0	0
Assets, fair value	375,726	406,506	411,758
Liabilities:
Derivatives, liabilities	0	0	0
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Cash equivalents	326,800	129,932	258,811
Marketable securities	0	0	5,004
Derivatives	3,613	1,769	12,446
Assets, fair value	330,413	131,701	276,261
Liabilities:
Derivatives, liabilities	22,850	21,308	1,052
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	8,300	9,000	6,300
Fair Value, Measurements, Nonrecurring | Significant Other Observable Inputs (Level 2) | Fair Value
Liabilities:
Repossessed inventory	$ 23,800	$ 19,600	$ 20,100