Derivatives and Fair Value of Financial Instruments (Details) (USD $)	3 Months Ended
	Mar. 30, 2013	Mar. 30, 2013 Commodities	Dec. 31, 2012 Commodities	Mar. 30, 2013 Interest rate swaps	Dec. 31, 2012 Interest rate swaps	Mar. 30, 2013 Foreign currencies	Dec. 31, 2012 Foreign currencies	Mar. 30, 2013 Money market funds	Dec. 31, 2012 Money market funds	Mar. 30, 2013 Corporate bonds	Dec. 31, 2012 Corporate bonds	Mar. 30, 2013 Enhanced cash mutual fund	Mar. 30, 2013 U.S. Government agency securities	Dec. 31, 2012 U.S. Government agency securities	Mar. 30, 2013 U.S. Treasury securities	Dec. 31, 2012 U.S. Treasury securities	Mar. 30, 2013 Emerging markets debt mutual fund	Dec. 31, 2012 Emerging markets debt mutual fund	Mar. 30, 2013 Collateralized mortgage obligations	Dec. 31, 2012 Collateralized mortgage obligations	Mar. 30, 2013 Asset backed debt securities	Dec. 31, 2012 Asset backed debt securities	Mar. 30, 2013 High yield trading debt securities	Dec. 31, 2012 High yield trading debt securities	Mar. 30, 2013 Emerging markets trading debt mutual fund	Dec. 31, 2012 Emerging markets trading debt mutual fund	Mar. 30, 2013 Emerging markets trading debt securities	Dec. 31, 2012 Emerging markets trading debt securities	Mar. 30, 2013 Recurring basis Balance at period end	Dec. 31, 2012 Recurring basis Balance at period end	Mar. 30, 2013 Recurring basis Balance at period end Commodities	Dec. 31, 2012 Recurring basis Balance at period end Commodities	Mar. 30, 2013 Recurring basis Balance at period end Interest rate swaps	Dec. 31, 2012 Recurring basis Balance at period end Interest rate swaps	Mar. 30, 2013 Recurring basis Balance at period end Foreign currencies	Dec. 31, 2012 Recurring basis Balance at period end Foreign currencies	Mar. 30, 2013 Recurring basis Balance at period end Money market funds Short-term investments	Dec. 31, 2012 Recurring basis Balance at period end Money market funds Short-term investments	Mar. 30, 2013 Recurring basis Balance at period end Money market funds Other current assets	Dec. 31, 2012 Recurring basis Balance at period end Money market funds Other current assets	Mar. 30, 2013 Recurring basis Balance at period end Corporate bonds Short-term investments	Dec. 31, 2012 Recurring basis Balance at period end Corporate bonds Short-term investments	Mar. 30, 2013 Recurring basis Balance at period end Corporate bonds Other current assets	Dec. 31, 2012 Recurring basis Balance at period end Corporate bonds Other current assets	Mar. 30, 2013 Recurring basis Balance at period end Enhanced cash mutual fund Short-term investments	Mar. 30, 2013 Recurring basis Balance at period end U.S. Government agency securities Short-term investments	Dec. 31, 2012 Recurring basis Balance at period end U.S. Government agency securities Short-term investments	Mar. 30, 2013 Recurring basis Balance at period end U.S. Government agency securities Other current assets	Dec. 31, 2012 Recurring basis Balance at period end U.S. Government agency securities Other current assets	Mar. 30, 2013 Recurring basis Balance at period end U.S. Treasury securities Short-term investments	Dec. 31, 2012 Recurring basis Balance at period end U.S. Treasury securities Short-term investments	Mar. 30, 2013 Recurring basis Balance at period end U.S. Treasury securities Other current assets	Dec. 31, 2012 Recurring basis Balance at period end U.S. Treasury securities Other current assets	Mar. 30, 2013 Recurring basis Balance at period end Emerging markets debt mutual fund Short-term investments	Dec. 31, 2012 Recurring basis Balance at period end Emerging markets debt mutual fund Short-term investments	Mar. 30, 2013 Recurring basis Balance at period end Collateralized mortgage obligations Short-term investments	Dec. 31, 2012 Recurring basis Balance at period end Collateralized mortgage obligations Short-term investments	Mar. 30, 2013 Recurring basis Balance at period end Asset backed debt securities Short-term investments	Dec. 31, 2012 Recurring basis Balance at period end Asset backed debt securities Short-term investments	Mar. 30, 2013 Recurring basis Balance at period end High yield trading debt securities Short-term investments	Dec. 31, 2012 Recurring basis Balance at period end High yield trading debt securities Short-term investments	Mar. 30, 2013 Recurring basis Balance at period end Emerging markets trading debt mutual fund Short-term investments	Dec. 31, 2012 Recurring basis Balance at period end Emerging markets trading debt mutual fund Short-term investments	Mar. 30, 2013 Recurring basis Balance at period end Emerging markets trading debt securities Short-term investments	Dec. 31, 2012 Recurring basis Balance at period end Emerging markets trading debt securities Short-term investments	Mar. 30, 2013 Recurring basis Balance at period end Other trading investments Short-term investments	Dec. 31, 2012 Recurring basis Balance at period end Other trading investments Short-term investments	Mar. 30, 2013 Recurring basis Balance at period end Domestic equity securities Other current assets	Dec. 31, 2012 Recurring basis Balance at period end Domestic equity securities Other current assets	Mar. 30, 2013 Recurring basis Balance at period end Foreign equity securities Other current assets	Dec. 31, 2012 Recurring basis Balance at period end Foreign equity securities Other current assets	Mar. 30, 2013 Recurring basis Balance at period end Fixed income mutual funds Other current assets	Dec. 31, 2012 Recurring basis Balance at period end Fixed income mutual funds Other current assets	Mar. 30, 2013 Recurring basis Balance at period end Other Other current assets	Dec. 31, 2012 Recurring basis Balance at period end Other Other current assets	Mar. 30, 2013 Recurring basis Level 1	Dec. 31, 2012 Recurring basis Level 1	Mar. 30, 2013 Recurring basis Level 1 Commodities	Dec. 31, 2012 Recurring basis Level 1 Commodities	Mar. 30, 2013 Recurring basis Level 1 Money market funds Short-term investments	Dec. 31, 2012 Recurring basis Level 1 Money market funds Short-term investments	Mar. 30, 2013 Recurring basis Level 1 Money market funds Other current assets	Dec. 31, 2012 Recurring basis Level 1 Money market funds Other current assets	Mar. 30, 2013 Recurring basis Level 1 Enhanced cash mutual fund Short-term investments	Mar. 30, 2013 Recurring basis Level 1 Emerging markets debt mutual fund Short-term investments	Dec. 31, 2012 Recurring basis Level 1 Emerging markets debt mutual fund Short-term investments	Mar. 30, 2013 Recurring basis Level 1 Emerging markets trading debt mutual fund Short-term investments	Dec. 31, 2012 Recurring basis Level 1 Emerging markets trading debt mutual fund Short-term investments	Mar. 30, 2013 Recurring basis Level 1 Other trading investments Short-term investments	Dec. 31, 2012 Recurring basis Level 1 Other trading investments Short-term investments	Mar. 30, 2013 Recurring basis Level 1 Domestic equity securities Other current assets	Dec. 31, 2012 Recurring basis Level 1 Domestic equity securities Other current assets	Mar. 30, 2013 Recurring basis Level 1 Foreign equity securities Other current assets	Dec. 31, 2012 Recurring basis Level 1 Foreign equity securities Other current assets	Mar. 30, 2013 Recurring basis Level 1 Fixed income mutual funds Other current assets	Dec. 31, 2012 Recurring basis Level 1 Fixed income mutual funds Other current assets	Mar. 30, 2013 Recurring basis Level 1 Other Other current assets	Dec. 31, 2012 Recurring basis Level 1 Other Other current assets	Mar. 30, 2013 Recurring basis Level 2	Dec. 31, 2012 Recurring basis Level 2	Dec. 31, 2012 Recurring basis Level 2 Commodities	Mar. 30, 2013 Recurring basis Level 2 Interest rate swaps	Dec. 31, 2012 Recurring basis Level 2 Interest rate swaps	Mar. 30, 2013 Recurring basis Level 2 Foreign currencies	Dec. 31, 2012 Recurring basis Level 2 Foreign currencies	Mar. 30, 2013 Recurring basis Level 2 Corporate bonds Short-term investments	Dec. 31, 2012 Recurring basis Level 2 Corporate bonds Short-term investments	Mar. 30, 2013 Recurring basis Level 2 Corporate bonds Other current assets	Dec. 31, 2012 Recurring basis Level 2 Corporate bonds Other current assets	Mar. 30, 2013 Recurring basis Level 2 U.S. Government agency securities Short-term investments	Dec. 31, 2012 Recurring basis Level 2 U.S. Government agency securities Short-term investments	Mar. 30, 2013 Recurring basis Level 2 U.S. Government agency securities Other current assets	Dec. 31, 2012 Recurring basis Level 2 U.S. Government agency securities Other current assets	Mar. 30, 2013 Recurring basis Level 2 U.S. Treasury securities Short-term investments	Dec. 31, 2012 Recurring basis Level 2 U.S. Treasury securities Short-term investments	Mar. 30, 2013 Recurring basis Level 2 U.S. Treasury securities Other current assets	Dec. 31, 2012 Recurring basis Level 2 U.S. Treasury securities Other current assets	Mar. 30, 2013 Recurring basis Level 2 Collateralized mortgage obligations Short-term investments	Dec. 31, 2012 Recurring basis Level 2 Collateralized mortgage obligations Short-term investments	Mar. 30, 2013 Recurring basis Level 2 Asset backed debt securities Short-term investments	Dec. 31, 2012 Recurring basis Level 2 Asset backed debt securities Short-term investments	Mar. 30, 2013 Recurring basis Level 2 High yield trading debt securities Short-term investments	Dec. 31, 2012 Recurring basis Level 2 High yield trading debt securities Short-term investments	Mar. 30, 2013 Recurring basis Level 2 Emerging markets trading debt securities Short-term investments	Dec. 31, 2012 Recurring basis Level 2 Emerging markets trading debt securities Short-term investments	Mar. 30, 2013 Recurring basis Level 2 Other trading investments Short-term investments	Dec. 31, 2012 Recurring basis Level 2 Other trading investments Short-term investments	Mar. 30, 2013 Recurring basis Level 2 Foreign equity securities Other current assets	Dec. 31, 2012 Recurring basis Level 2 Foreign equity securities Other current assets	Mar. 30, 2013 Recurring basis Level 2 Other Other current assets	Dec. 31, 2012 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								138,756,000	126,537,000	66,661,000	69,214,000	25,011,000	22,336,000	23,775,000	20,855,000	17,169,000	18,750,000	18,734,000	14,716,000	15,162,000	12,544,000	12,238,000															138,756,000	126,537,000			66,661,000	69,214,000			25,011,000	22,336,000	23,775,000			20,855,000	17,169,000			18,750,000	18,734,000	14,716,000	15,162,000	12,544,000	12,238,000																					138,756,000	126,537,000			25,011,000	18,750,000	18,734,000																				66,661,000	69,214,000			22,336,000	23,775,000			20,855,000	17,169,000			14,716,000	15,162,000	12,544,000	12,238,000
Trading securities																							24,190,000	23,406,000	3,237,000	3,237,000	2,761,000	2,600,000											2,594,000	3,157,000			94,000	60,000				1,687,000	2,117,000			1,984,000	1,567,000							24,190,000	23,406,000	3,237,000	3,237,000	2,761,000	2,600,000	985,000	1,307,000	20,360,000	15,864,000	7,371,000	6,831,000	6,956,000	7,153,000	245,000	239,000							2,594,000	3,157,000				3,237,000	3,237,000	453,000	822,000	20,360,000	15,864,000	5,011,000	4,218,000	6,956,000	7,153,000	202,000	187,000										94,000	60,000			1,687,000	2,117,000			1,984,000	1,567,000					24,190,000	23,406,000	2,761,000	2,600,000	532,000	485,000	2,360,000	2,613,000	43,000	52,000
Derivatives		4,253,000	6,916,000			5,766,000																									4,253,000	6,916,000			5,766,000																																											4,253,000	6,699,000																						217,000			5,766,000
Margin account		15,222,000	14,063,000																												15,222,000	14,063,000
Derivative assets and liabilities, net basis		9,486,000	13,867,000																												9,486,000	13,867,000
Total Assets																													402,112,000	357,283,000																																														225,583,000	186,608,000																						176,529,000	170,675,000
Liabilities:
Derivatives		9,989,000	7,112,000	8,803,000	9,810,000		4,157,000																								9,989,000	7,112,000	8,803,000	9,810,000		4,157,000																																										9,989,000	7,112,000																							8,803,000	9,810,000		4,157,000
Total Liabilities																													$ 18,792,000	$ 21,079,000																																														$ 9,989,000	$ 7,112,000																						$ 8,803,000	$ 13,967,000