Marketable Securities - Schedule of Amortized Cost and Estimated Fair Value of Marketable Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Jun. 27, 2020	Dec. 28, 2019
Investments Debt And Equity Securities [Abstract]
Amortized Cost, Due in one year or less	$ 380,256
Amortized Cost, Due after one year through five years	849,952
Amortized Cost, Due after five years through ten years	115,855
Amortized Cost, Due after ten years	6,793
Amortized Cost	1,352,856	$ 1,578,937
Fair Value, Due in one year or less	380,880
Fair Value, Due after one year through five years	868,799
Fair Value, Due after five years through ten years	118,061
Fair Value, Due after ten years	6,161
Fair Value, Total	$ 1,373,901	$ 1,581,938