Derivatives and Fair Value of Financial Instruments (Details 2) (USD $)	Sep. 28, 2013	Dec. 31, 2012
Amortized Cost
Schedule of amortized cost and estimated fair values of investments and long term debt
Available-for-sale securities	$ 214,408,000	$ 279,556,000
Trading securities	30,073,000	28,508,000
Long-term debt	116,028,000	145,963,000
Fair Value
Schedule of amortized cost and estimated fair values of investments and long term debt
Available-for-sale securities	214,349,000	282,829,000
Trading securities	30,646,000	30,550,000
Long-term debt	$ 118,875,000	$ 149,333,000