Marketable Securities (Maturities of Marketable Securities) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 29, 2012	Dec. 31, 2011
Marketable Securities [Abstract]
Amortized Cost, Due within one year	$ 5,628
Fair Value, Due within one year	5,478
Amortized Cost, Due after one year through five years	46,213
Fair Value, Due after one year through five years	46,236
Amortized Cost, Due after five years through ten years	18,679
Fair Value, Due after five years through ten years	20,216
Amortized Cost, Due after ten years	1,500
Fair Value, Due after ten years	1,500
Amortized Cost, Equity securities	1,136
Fair Value, Equity securities	9,888
Available-for-sale Securities, Amortized Cost Basis, Total	73,156	80,101
Available-for-sale Securities, Fair Value, Total	$ 83,318	$ 89,348