Cash, Cash Equivalents And Marketable Securities (Summary Of The Amortized Costs And Fair Values Of Marketable Securities) (Details) - USD ($) $ in Thousands	Oct. 04, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
MARKETABLE SECURITIES, Amortized Cost	$ 24,585	$ 22,409
MARKETABLE SECURITIES, Fair Value	24,579	22,404
MARKETABLE SECURITIES, Gross Unrealized Gains	7	5
MARKETABLE SECURITIES, Gross Unrealized Losses	13	10
Tax-Exempt Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
MARKETABLE SECURITIES, Amortized Cost	11,969	8,809
MARKETABLE SECURITIES, Fair Value	11,963	8,804
MARKETABLE SECURITIES, Gross Unrealized Gains	7	5
MARKETABLE SECURITIES, Gross Unrealized Losses	13	10
Variable Rate Demand Notes [Member]
Schedule of Available-for-sale Securities [Line Items]
MARKETABLE SECURITIES, Amortized Cost	12,616	13,600
MARKETABLE SECURITIES, Fair Value	$ 12,616	$ 13,600