Marketable Securities (Schedule Of Marketable Securities) (Details) - USD ($) $ in Thousands	Dec. 28, 2019	Dec. 29, 2018
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 52,264	$ 46,699
Gross Unrealized Holding Gains	2,091	426
Gross Unrealized Holding Losses	(18)	(53)
Fair Value	54,337
Fair value	63,538	54,298
Equity Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Debt Securities, Available-for-sale [Line Items]
Equity securities, Fair Value	9,201	7,226
Municipal Bonds [Member] \| Fair Value, Inputs, Level 2 [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	52,264	46,699
Gross Unrealized Holding Gains	2,091	426
Gross Unrealized Holding Losses	(18)	(53)
Fair Value	$ 54,337	$ 47,072

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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