Marketable Securities (Schedule Of Maturities of Marketable Securities) (Details) - USD ($) $ in Thousands	Mar. 30, 2019	Dec. 29, 2018
Marketable Securities [Abstract]
Amortized Cost, Due within one year	$ 6,485
Fair Value, Due within one year	6,492
Amortized Cost, Due after one year through five years	22,342
Fair Value, Due after one year through five years	22,756
Amortized Cost, Due after five years through ten years	20,151
Fair Value, Due after five years through ten years	20,963
Amortized Cost, Due after ten years	998
Fair Value, Due after ten years	1,002
Amortized Cost, Equity securities	1,198
Fair Value, Equity securities	7,851
Amortized Cost	51,174	$ 47,897
Fair Value	$ 59,064	$ 54,298