Derivatives and Fair Value of Financial Instruments (Details) (USD $)	6 Months Ended
	Jun. 28, 2014	Jun. 28, 2014 Commodities	Dec. 31, 2013 Commodities	Jun. 28, 2014 Money market funds	Dec. 31, 2013 Money market funds	Jun. 28, 2014 Corporate bonds	Dec. 31, 2013 Corporate bonds	Jun. 28, 2014 U.S. Government agency securities	Dec. 31, 2013 U.S. Government agency securities	Jun. 28, 2014 Asset backed debt securities	Dec. 31, 2013 Asset backed debt securities	Jun. 28, 2014 Collateralized mortgage obligations	Dec. 31, 2013 Collateralized mortgage obligations	Jun. 28, 2014 U.S. Treasury securities	Dec. 31, 2013 U.S. Treasury securities	Dec. 31, 2013 Emerging markets debt mutual fund	Jun. 28, 2014 High yield debt securities	Dec. 31, 2013 High yield debt securities	Jun. 28, 2014 Equity mutual fund	Jun. 28, 2014 Money market funds held in trading accounts	Dec. 31, 2013 Money market funds held in trading accounts	Jun. 28, 2014 Domestic equity ETF	Jun. 28, 2014 Emerging markets trading debt mutual fund	Dec. 31, 2013 Emerging markets trading debt mutual fund	Jun. 28, 2014 Emerging markets trading debt securities	Dec. 31, 2013 Emerging markets trading debt securities	Jun. 28, 2014 Recurring basis Balance at period end	Dec. 31, 2013 Recurring basis Balance at period end	Jun. 28, 2014 Recurring basis Balance at period end Commodities	Dec. 31, 2013 Recurring basis Balance at period end Commodities	Jun. 28, 2014 Recurring basis Balance at period end Interest rate swaps	Dec. 31, 2013 Recurring basis Balance at period end Interest rate swaps	Jun. 28, 2014 Recurring basis Balance at period end Foreign currencies	Dec. 31, 2013 Recurring basis Balance at period end Foreign currencies	Jun. 28, 2014 Recurring basis Balance at period end Other current assets Commodities	Dec. 31, 2013 Recurring basis Balance at period end Other current assets Commodities	Jun. 28, 2014 Recurring basis Balance at period end Money market funds Short-term investments	Dec. 31, 2013 Recurring basis Balance at period end Money market funds Short-term investments	Jun. 28, 2014 Recurring basis Balance at period end Money market funds Other current assets	Dec. 31, 2013 Recurring basis Balance at period end Money market funds Other current assets	Jun. 28, 2014 Recurring basis Balance at period end Corporate bonds Short-term investments	Dec. 31, 2013 Recurring basis Balance at period end Corporate bonds Short-term investments	Jun. 28, 2014 Recurring basis Balance at period end U.S. Government agency securities Short-term investments	Dec. 31, 2013 Recurring basis Balance at period end U.S. Government agency securities Short-term investments	Jun. 28, 2014 Recurring basis Balance at period end Asset backed debt securities Short-term investments	Dec. 31, 2013 Recurring basis Balance at period end Asset backed debt securities Short-term investments	Jun. 28, 2014 Recurring basis Balance at period end Collateralized mortgage obligations Short-term investments	Dec. 31, 2013 Recurring basis Balance at period end Collateralized mortgage obligations Short-term investments	Jun. 28, 2014 Recurring basis Balance at period end U.S. Treasury securities Short-term investments	Dec. 31, 2013 Recurring basis Balance at period end U.S. Treasury securities Short-term investments	Dec. 31, 2013 Recurring basis Balance at period end Emerging markets debt mutual fund Short-term investments	Jun. 28, 2014 Recurring basis Balance at period end High yield debt securities Short-term investments	Dec. 31, 2013 Recurring basis Balance at period end High yield debt securities Short-term investments	Jun. 28, 2014 Recurring basis Balance at period end Equity mutual fund Short-term investments	Jun. 28, 2014 Recurring basis Balance at period end Money market funds held in trading accounts Short-term investments	Dec. 31, 2013 Recurring basis Balance at period end Money market funds held in trading accounts Short-term investments	Jun. 28, 2014 Recurring basis Balance at period end Domestic equity ETF Short-term investments	Jun. 28, 2014 Recurring basis Balance at period end Emerging markets trading debt mutual fund Short-term investments	Dec. 31, 2013 Recurring basis Balance at period end Emerging markets trading debt mutual fund Short-term investments	Jun. 28, 2014 Recurring basis Balance at period end Emerging markets trading debt securities Short-term investments	Dec. 31, 2013 Recurring basis Balance at period end Emerging markets trading debt securities Short-term investments	Jun. 28, 2014 Recurring basis Balance at period end Other trading investments Short-term investments	Dec. 31, 2013 Recurring basis Balance at period end Other trading investments Short-term investments	Jun. 28, 2014 Recurring basis Balance at period end Domestic equity securities Other current assets	Dec. 31, 2013 Recurring basis Balance at period end Domestic equity securities Other current assets	Jun. 28, 2014 Recurring basis Balance at period end Foreign equity securities Other current assets	Dec. 31, 2013 Recurring basis Balance at period end Foreign equity securities Other current assets	Jun. 28, 2014 Recurring basis Balance at period end Fixed income mutual funds Other current assets	Dec. 31, 2013 Recurring basis Balance at period end Fixed income mutual funds Other current assets	Jun. 28, 2014 Recurring basis Balance at period end Other Other current assets	Dec. 31, 2013 Recurring basis Balance at period end Other Other current assets	Jun. 28, 2014 Recurring basis Level 1	Dec. 31, 2013 Recurring basis Level 1	Jun. 28, 2014 Recurring basis Level 1 Commodities	Dec. 31, 2013 Recurring basis Level 1 Commodities	Jun. 28, 2014 Recurring basis Level 1 Money market funds Short-term investments	Dec. 31, 2013 Recurring basis Level 1 Money market funds Short-term investments	Jun. 28, 2014 Recurring basis Level 1 Money market funds Other current assets	Dec. 31, 2013 Recurring basis Level 1 Money market funds Other current assets	Dec. 31, 2013 Recurring basis Level 1 Emerging markets debt mutual fund Short-term investments	Jun. 28, 2014 Recurring basis Level 1 Equity mutual fund Short-term investments	Jun. 28, 2014 Recurring basis Level 1 Money market funds held in trading accounts Short-term investments	Dec. 31, 2013 Recurring basis Level 1 Money market funds held in trading accounts Short-term investments	Jun. 28, 2014 Recurring basis Level 1 Domestic equity ETF Short-term investments	Jun. 28, 2014 Recurring basis Level 1 Emerging markets trading debt mutual fund Short-term investments	Dec. 31, 2013 Recurring basis Level 1 Emerging markets trading debt mutual fund Short-term investments	Jun. 28, 2014 Recurring basis Level 1 Domestic equity securities Other current assets	Dec. 31, 2013 Recurring basis Level 1 Domestic equity securities Other current assets	Jun. 28, 2014 Recurring basis Level 1 Foreign equity securities Other current assets	Dec. 31, 2013 Recurring basis Level 1 Foreign equity securities Other current assets	Jun. 28, 2014 Recurring basis Level 1 Fixed income mutual funds Other current assets	Dec. 31, 2013 Recurring basis Level 1 Fixed income mutual funds Other current assets	Jun. 28, 2014 Recurring basis Level 1 Other Other current assets	Dec. 31, 2013 Recurring basis Level 1 Other Other current assets	Jun. 28, 2014 Recurring basis Level 2	Dec. 31, 2013 Recurring basis Level 2	Jun. 28, 2014 Recurring basis Level 2 Commodities	Dec. 31, 2013 Recurring basis Level 2 Commodities	Jun. 28, 2014 Recurring basis Level 2 Interest rate swaps	Dec. 31, 2013 Recurring basis Level 2 Interest rate swaps	Jun. 28, 2014 Recurring basis Level 2 Foreign currencies	Dec. 31, 2013 Recurring basis Level 2 Foreign currencies	Jun. 28, 2014 Recurring basis Level 2 Corporate bonds Short-term investments	Dec. 31, 2013 Recurring basis Level 2 Corporate bonds Short-term investments	Jun. 28, 2014 Recurring basis Level 2 U.S. Government agency securities Short-term investments	Dec. 31, 2013 Recurring basis Level 2 U.S. Government agency securities Short-term investments	Jun. 28, 2014 Recurring basis Level 2 Asset backed debt securities Short-term investments	Dec. 31, 2013 Recurring basis Level 2 Asset backed debt securities Short-term investments	Jun. 28, 2014 Recurring basis Level 2 Collateralized mortgage obligations Short-term investments	Dec. 31, 2013 Recurring basis Level 2 Collateralized mortgage obligations Short-term investments	Jun. 28, 2014 Recurring basis Level 2 U.S. Treasury securities Short-term investments	Dec. 31, 2013 Recurring basis Level 2 U.S. Treasury securities Short-term investments	Jun. 28, 2014 Recurring basis Level 2 High yield debt securities Short-term investments	Dec. 31, 2013 Recurring basis Level 2 High yield debt securities Short-term investments	Jun. 28, 2014 Recurring basis Level 2 Emerging markets trading debt securities Short-term investments	Dec. 31, 2013 Recurring basis Level 2 Emerging markets trading debt securities Short-term investments	Jun. 28, 2014 Recurring basis Level 2 Other trading investments Short-term investments	Dec. 31, 2013 Recurring basis Level 2 Other trading investments Short-term investments	Jun. 28, 2014 Recurring basis Level 2 Foreign equity securities Other current assets	Dec. 31, 2013 Recurring basis Level 2 Foreign equity securities Other current assets	Jun. 28, 2014 Recurring basis Level 2 Other Other current assets	Dec. 31, 2013 Recurring basis Level 2 Other Other current assets
Derivatives and Fair Value of Financial Instruments
Transfers that occurred into or out of level 1	$ 0
Transfers that occurred into or out of level 2	0
Transfers that occurred into or out of level 3	0
Assets:
Available-for-sale securities				66,993,000	88,430,000	49,921,000	70,258,000	43,629,000	27,147,000	10,791,000	8,477,000	5,584,000	7,600,000	5,035,000	5,223,000	16,941,000																					66,993,000	88,430,000			49,921,000	70,258,000	43,629,000	27,147,000	10,791,000	8,477,000	5,584,000	7,600,000	5,035,000	5,223,000	16,941,000																									66,993,000	88,430,000			16,941,000																							49,921,000	70,258,000	43,629,000	27,147,000	10,791,000	8,477,000	5,584,000	7,600,000	5,035,000	5,223,000
Trading securities																	103,163,000	50,428,000	25,017,000	5,728,000	11,033,000	5,107,000	2,988,000	2,858,000	621,000	1,336,000													2,273,000	1,931,000												103,163,000	50,428,000	25,017,000	5,728,000	11,033,000	5,107,000	2,988,000	2,858,000	621,000	1,336,000	557,000	918,000	30,869,000	26,672,000	8,450,000	9,570,000	4,945,000	3,974,000	2,083,000	3,203,000							2,273,000	1,931,000		25,017,000	5,728,000	11,033,000	5,107,000	2,988,000	2,858,000	30,869,000	26,672,000	7,049,000	7,317,000	4,945,000	3,974,000	177,000	1,628,000																			103,163,000	50,428,000	621,000	1,336,000	557,000	918,000	1,401,000	2,253,000	1,906,000	1,575,000
Derivatives																													9,560,000	2,331,000			2,101,000	2,763,000																																								9,560,000	2,331,000																										2,101,000	2,763,000
Total Assets																											385,415,000	341,093,000																																												160,706,000	163,115,000																						224,709,000	177,978,000
Margin account		44,039,000	29,822,000																										44,039,000	29,822,000
Derivative assets and liabilities, net basis																																			15,585,000	16,731,000
Liabilities:
Derivatives																													38,166,000	16,014,000	6,901,000	4,103,000	378,000	101,000																																								38,014,000	15,422,000																						152,000	592,000	6,901,000	4,103,000	378,000	101,000
Total Liabilities																											$ 45,445,000	$ 20,218,000																																												$ 38,014,000	$ 15,422,000																						$ 7,431,000	$ 4,796,000