Derivatives and Fair Value of Financial Instruments (Details) (USD $)	9 Months Ended
	Sep. 27, 2014	Sep. 27, 2014 Commodities	Dec. 31, 2013 Commodities	Sep. 27, 2014 Other current assets Commodities	Dec. 31, 2013 Other current assets Commodities	Sep. 27, 2014 Other current assets Foreign currencies	Dec. 31, 2013 Other current assets Foreign currencies	Sep. 27, 2014 Other current liability Commodities	Dec. 31, 2013 Other current liability Commodities	Sep. 27, 2014 Other current liability Interest rate swaps	Dec. 31, 2013 Other current liability Interest rate swaps	Sep. 27, 2014 Other current liability Foreign currencies	Dec. 31, 2013 Other current liability Foreign currencies	Sep. 27, 2014 Money market funds	Dec. 31, 2013 Money market funds	Sep. 27, 2014 Corporate bonds	Dec. 31, 2013 Corporate bonds	Sep. 27, 2014 U.S. Government agency securities	Dec. 31, 2013 U.S. Government agency securities	Sep. 27, 2014 Asset backed debt securities	Dec. 31, 2013 Asset backed debt securities	Sep. 27, 2014 Collateralized mortgage obligations	Dec. 31, 2013 Collateralized mortgage obligations	Sep. 27, 2014 U.S. Treasury securities	Dec. 31, 2013 U.S. Treasury securities	Dec. 31, 2013 Emerging markets debt mutual fund	Sep. 27, 2014 High yield debt securities	Dec. 31, 2013 High yield debt securities	Sep. 27, 2014 Equity mutual fund	Sep. 27, 2014 Domestic equity ETF	Sep. 27, 2014 Emerging markets trading debt mutual fund	Dec. 31, 2013 Emerging markets trading debt mutual fund	Sep. 27, 2014 Emerging markets trading debt securities	Dec. 31, 2013 Emerging markets trading debt securities	Sep. 27, 2014 Money market funds held in trading accounts	Dec. 31, 2013 Money market funds held in trading accounts	Sep. 27, 2014 Recurring basis Balance at period end	Dec. 31, 2013 Recurring basis Balance at period end	Sep. 27, 2014 Recurring basis Balance at period end Commodities	Dec. 31, 2013 Recurring basis Balance at period end Commodities	Sep. 27, 2014 Recurring basis Balance at period end Interest rate swaps	Dec. 31, 2013 Recurring basis Balance at period end Interest rate swaps	Sep. 27, 2014 Recurring basis Balance at period end Foreign currencies	Dec. 31, 2013 Recurring basis Balance at period end Foreign currencies	Sep. 27, 2014 Recurring basis Balance at period end Other current assets Commodities	Dec. 31, 2013 Recurring basis Balance at period end Other current assets Commodities	Sep. 27, 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	Sep. 27, 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	Sep. 27, 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	Sep. 27, 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	Sep. 27, 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	Sep. 27, 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	Sep. 27, 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	Sep. 27, 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	Sep. 27, 2014 Recurring basis Balance at period end Equity mutual fund Short-term investments	Sep. 27, 2014 Recurring basis Balance at period end Domestic equity ETF Short-term investments	Sep. 27, 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	Sep. 27, 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	Sep. 27, 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	Sep. 27, 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	Sep. 27, 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	Sep. 27, 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	Sep. 27, 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	Sep. 27, 2014 Recurring basis Balance at period end Other Other current assets	Dec. 31, 2013 Recurring basis Balance at period end Other Other current assets	Sep. 27, 2014 Recurring basis Level 1	Dec. 31, 2013 Recurring basis Level 1	Sep. 27, 2014 Recurring basis Level 1 Commodities	Dec. 31, 2013 Recurring basis Level 1 Commodities	Sep. 27, 2014 Recurring basis Level 1 Money market funds Short-term investments	Dec. 31, 2013 Recurring basis Level 1 Money market funds Short-term investments	Sep. 27, 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	Sep. 27, 2014 Recurring basis Level 1 Equity mutual fund Short-term investments	Sep. 27, 2014 Recurring basis Level 1 Domestic equity ETF Short-term investments	Sep. 27, 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	Sep. 27, 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	Sep. 27, 2014 Recurring basis Level 1 Domestic equity securities Other current assets	Dec. 31, 2013 Recurring basis Level 1 Domestic equity securities Other current assets	Sep. 27, 2014 Recurring basis Level 1 Foreign equity securities Other current assets	Dec. 31, 2013 Recurring basis Level 1 Foreign equity securities Other current assets	Sep. 27, 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	Sep. 27, 2014 Recurring basis Level 1 Other Other current assets	Dec. 31, 2013 Recurring basis Level 1 Other Other current assets	Sep. 27, 2014 Recurring basis Level 2	Dec. 31, 2013 Recurring basis Level 2	Sep. 27, 2014 Recurring basis Level 2 Commodities	Dec. 31, 2013 Recurring basis Level 2 Commodities	Sep. 27, 2014 Recurring basis Level 2 Interest rate swaps	Dec. 31, 2013 Recurring basis Level 2 Interest rate swaps	Sep. 27, 2014 Recurring basis Level 2 Foreign currencies	Dec. 31, 2013 Recurring basis Level 2 Foreign currencies	Sep. 27, 2014 Recurring basis Level 2 Corporate bonds Short-term investments	Dec. 31, 2013 Recurring basis Level 2 Corporate bonds Short-term investments	Sep. 27, 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	Sep. 27, 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	Sep. 27, 2014 Recurring basis Level 2 Collateralized mortgage obligations Short-term investments	Dec. 31, 2013 Recurring basis Level 2 Collateralized mortgage obligations Short-term investments	Sep. 27, 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	Sep. 27, 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	Sep. 27, 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	Sep. 27, 2014 Recurring basis Level 2 Other trading investments Short-term investments	Dec. 31, 2013 Recurring basis Level 2 Other trading investments Short-term investments	Dec. 31, 2013 Recurring basis Level 2 Foreign equity securities Other current assets	Sep. 27, 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														62,965,000	88,430,000	10,439,000	70,258,000	10,355,000	27,147,000	2,244,000	8,477,000	1,214,000	7,600,000	521,000	5,223,000	16,941,000																					62,965,000	88,430,000			10,439,000	70,258,000	10,355,000	27,147,000	2,244,000	8,477,000	1,214,000	7,600,000	521,000	5,223,000	16,941,000																									62,965,000	88,430,000			16,941,000																							10,439,000	70,258,000	10,355,000	27,147,000	2,244,000	8,477,000	1,214,000	7,600,000	521,000	5,223,000
Trading securities																											188,645,000	50,428,000	65,050,000	15,203,000	2,849,000	2,858,000	1,660,000	1,336,000	390,000	11,033,000													2,727,000	1,931,000												188,645,000	50,428,000	65,050,000	15,203,000	2,849,000	2,858,000	1,660,000	1,336,000	390,000	11,033,000	1,430,000	918,000	29,632,000	26,672,000	8,018,000	9,570,000	4,362,000	3,974,000	1,357,000	3,203,000							2,727,000	1,931,000		65,050,000	15,203,000	2,849,000	2,858,000	390,000	11,033,000	29,632,000	26,672,000	8,018,000	7,317,000	4,362,000	3,974,000	616,000	1,628,000																			188,645,000	50,428,000	1,660,000	1,336,000	1,430,000	918,000	2,253,000	741,000	1,575,000
Derivatives				20,394,000	2,331,000	4,674,000	2,763,000																																20,394,000	2,331,000			4,674,000	2,763,000																																								20,394,000	2,331,000																										4,674,000	2,763,000
Total Assets																																					434,129,000	341,093,000																																												212,206,000	163,115,000																						221,923,000	177,978,000
Margin account		13,006,000	29,822,000																																				13,006,000	29,822,000
Derivative assets and liabilities, net basis				17,426,000	16,731,000			109,000	592,000																																				17,426,000	16,731,000
Liabilities:
Derivatives								16,083,000	16,014,000	5,766,000	4,103,000	218,000	101,000																										16,083,000	16,014,000	5,766,000	4,103,000	218,000	101,000																																								15,974,000	15,422,000																						109,000	592,000	5,766,000	4,103,000	218,000	101,000
Total Liabilities																																					$ 22,067,000	$ 20,218,000																																												$ 15,974,000	$ 15,422,000																						$ 6,093,000	$ 4,796,000