Marketable Securities (Maturities of Marketable Securities) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 30, 2013	Dec. 29, 2012
Marketable Securities [Abstract]
Amortized Cost, Due within one year	$ 4,438
Fair Value, Due within one year	4,317
Amortized Cost, Due after one year through five years	47,979
Fair Value, Due after one year through five years	47,766
Amortized Cost, Due after five years through ten years	14,113
Fair Value, Due after five years through ten years	15,241
Amortized Cost, Due after ten years	1,501
Fair Value, Due after ten years	1,501
Amortized Cost, Equity securities	1,136
Fair Value, Equity securities	9,854
Available-for-sale Securities, Amortized Cost Basis, Total	69,167	73,976
Available-for-sale Securities, Fair Value, Total	$ 78,679	$ 82,501