Earnings per Unit (Details)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2013	Jul. 01, 2012	Jun. 30, 2013	Jul. 01, 2012	Jun. 30, 2013	Jul. 01, 2012
Basic weighted average units outstanding	55,484,000	55,481,000	55,464,000	55,433,000	55,446,000	55,389,000
Effect of dilutive units:
Unit options and restricted unit awards	152,000	2,000	0	0	84,000	3,000
Phantom units	186,000	335,000	0	0	261,000	452,000
Diluted weighted average units outstanding	55,822,000	55,818,000	55,464,000	55,433,000	55,791,000	55,844,000
Net income (loss) per limited partner unit	0.85	0.66	(1.11)	(0.52)	1.24	2.11
Net income (loss) per limited partner unit	0.85	0.66	(1.11)	(0.52)	1.24	2.10
Unit Options [Member]
Effect of dilutive units:
Antidilutive securities excluded from the computation of earnings per unit	0	66,000	8,900	31,000	8,500	41,500