Cash, Cash Equivalents And Marketable Securities (Narrative) (Details) (USD $)	3 Months Ended
	Mar. 30, 2014	Mar. 31, 2013
Transfers into Level 2	$ 0
Transfers out of Level 2	0
Proceeds from sales of available-for-sale securities	9,912,000	2,264,000
Gross gains or losses related to sales of marketable securities	0	0
Net unrealized losses included in accumulated other comprehensive income, before taxes	7,000	12,000
Contractual maturities of marketable securities within 1 year	12,773,000
Contractual maturities of marketable securities, years 2-5	3,330,000
Contractual maturities of marketable securities, years 6-10	4,822,000
Contractual maturities of marketable securities, after 10 years	6,782,000
Marketable securities liquidation period	7 days
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Reclassification out of AOCI	$ 0	$ 0