Earnings per Unit (Details)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 29, 2013	Sep. 30, 2012	Sep. 29, 2013	Sep. 30, 2012	Sep. 29, 2013	Sep. 30, 2012
Basic weighted average units outstanding	55,485,000	55,611,000	55,472,000	55,473,000	55,460,000	55,440,000
Effect of dilutive units:
Unit options and restricted unit awards	189,000	45,000	146,000	42,000	120,000	31,000
Phantom units	189,000	336,000	185,000	333,000	224,000	416,000
Diluted weighted average units outstanding	55,863,000	55,992,000	55,803,000	55,848,000	55,804,000	55,887,000
Net income per limited partner unit	3.43	2.54	2.32	2.02	2.13	1.91
Net income (loss) per limited partner unit	3.41	2.52	2.31	2.01	2.12	1.89
Unit Options [Member]
Effect of dilutive units:
Antidilutive securities excluded from the computation of earnings per unit	0	66,000	7,000	34,000	4,000	36,000