Quarterly Financial Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						4 Months Ended		12 Months Ended
	Jan. 02, 2016	Oct. 10, 2015	Jul. 18, 2015	Jan. 03, 2015	Oct. 04, 2014	Jul. 12, 2014	Apr. 25, 2015	Apr. 19, 2014	Jan. 02, 2016	Jan. 03, 2015	Dec. 28, 2013
Quarterly Financial Information Disclosure [Abstract]
Sales	$ 858,363	$ 885,302	$ 888,795	$ 877,333	$ 844,932	$ 872,791	$ 1,146,045	$ 1,153,917	$ 3,778,505	$ 3,748,973	$ 3,732,616
Materials, supplies, labor and other production costs (exclusive of depreciation and amortization shown separately)	455,939	464,045	457,253	453,759	442,978	458,019	585,916	595,877	1,963,153	1,950,633	1,972,221
Net income	$ 32,246	$ 43,796	$ 51,760	$ 28,010	$ 44,599	$ 42,064	$ 61,389	$ 61,066	$ 189,191	$ 175,739	$ 230,894
Basic net income per share	$ 0.15	$ 0.21	$ 0.25	$ 0.13	$ 0.21	$ 0.20	$ 0.29	$ 0.29			$ 1.11
Diluted net income per share	$ 0.15	$ 0.21	$ 0.24	$ 0.13	$ 0.21	$ 0.20	$ 0.29	$ 0.29			$ 1.09