Investment in National Beef Packing Company, LLC (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 28, 2013	Sep. 29, 2012	Sep. 28, 2013	Sep. 29, 2012
Schedule of Investments [Line Items]
Net sales	$ 0	$ 0	$ 0	$ 0
Costs and expenses:
Cost of sales	0	0	0	0
Selling, general, and administrative expenses	719	1,117	3,077	4,570
Depreciation and amortization	1	2	5	5
Total costs and expenses	720	1,119	3,082	4,575
Operating income	(720)	(1,119)	(3,082)	(4,575)
Other income (expense):
Interest income	10	10	30	45
Interest expense	(19)	(19)	(57)	(49)
Other, net	6	0	282	(107)
Income before taxes	6,532	5,157	5,403	5,927
Income tax expense	0	0	0	0
Net income	6,532	5,157	5,403	5,927
National Beef Packing Company, LLC
Schedule of Investments [Line Items]
Net sales	1,920,747	1,909,204	5,629,564	5,613,374
Costs and expenses:
Cost of sales	1,832,908	1,830,129	5,455,755	5,430,675
Selling, general, and administrative expenses	14,489	13,481	42,386	41,873
Depreciation and amortization	22,250	20,803	65,838	61,868
Total costs and expenses	1,869,647	1,864,413	5,563,979	5,534,416
Operating income	51,100	44,791	65,585	78,958
Other income (expense):
Interest income	2	30	9	40
Interest expense	(2,944)	(2,988)	(9,428)	(9,288)
Other, net	153	126	(1,082)	1,589
Income before taxes	48,311	41,959	55,084	71,299
Income tax expense	(177)	(409)	(737)	(1,145)
Net income	48,134	41,550	54,347	70,154
Less: net income attributable to Kansas City Steak Company, LLC	0	146	255	254
Net income attributable to NBP	48,134	41,696	54,602	70,408
NBP's net income attributable to USPB	$ 7,255	$ 6,285	$ 8,230	$ 10,613