Cash, Cash Equivalents And Marketable Securities (Summary Of The Amortized Costs And Fair Values Of Marketable Securities) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 29, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
MARKETABLE SECURITIES, Amortized Cost	$ 44,282	$ 55,504
MARKETABLE SECURITIES, Fair Value	44,321	55,586
MARKETABLE SECURITIES, Gross Unrealized Gains	42	94
MARKETABLE SECURITIES - Gross Unrealized Losses	3	12
Tax-Exempt Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
MARKETABLE SECURITIES, Amortized Cost	23,591	24,412
MARKETABLE SECURITIES, Fair Value	23,630	24,494
MARKETABLE SECURITIES, Gross Unrealized Gains	42	94
MARKETABLE SECURITIES - Gross Unrealized Losses	3	12
Variable Rate Demand Notes [Member]
Schedule of Available-for-sale Securities [Line Items]
MARKETABLE SECURITIES, Amortized Cost	20,691	31,092
MARKETABLE SECURITIES, Fair Value	$ 20,691	$ 31,092