Note 5. Fair value and carrying value of partnership interest (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2015	Sep. 24, 2014	Sep. 25, 2013
Fair Value
Fair value of partnership interest, beginning	$ 620,811	$ 776,899	$ 455,297	$ 54,608
Investment partnership gains (losses)	156,088	(110,956)	1,436	23,053
Contribution of cash and securities (net of distributions) to investment partnership		68,725	164,078	377,636
Increase in proportionate share of Company stock held	0	0	0	0
Partnership interest, ending	776,899	734,668	620,811	455,297
Company Common Stock
Fair value of partnership interest, beginning	63,573	78,917	57,598	43,580
Investment partnership gains (losses)	11,386	(71,600)	(12,619)	2,985
Contribution of cash and securities (net of distributions) to investment partnership		0	0	0
Increase in proportionate share of Company stock held	3,958	255,662	18,594	11,033
Partnership interest, ending	78,917	262,979	63,573	57,598
Carry Value
Fair value of partnership interest, beginning	557,238	697,982	397,699	11,028
Investment partnership gains (losses)	144,702	(39,356)	14,055	20,068
Contribution of cash and securities (net of distributions) to investment partnership		68,725	164,078	377,636
Increase in proportionate share of Company stock held	(3,958)	(255,662)	(18,594)	(11,033)
Partnership interest, ending	$ 697,982	$ 471,689	$ 557,238	$ 397,699