Marketable Securities (Available For Sale Securities) (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 28, 2013	Dec. 29, 2012
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 67,667	$ 73,976
Gross Unrealized Holding Gains	7,603	9,022
Gross Unrealized Holding Losses	(1,581)	(497)
Fair Value	73,689	82,501
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	970	1,136
Gross Unrealized Holding Gains	6,894	7,714
Fair Value	7,864	8,850
Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	66,697	72,840
Gross Unrealized Holding Gains	709	1,308
Gross Unrealized Holding Losses	(1,581)	(497)
Fair Value	$ 65,825	$ 73,651