Quarterly Financial Information (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 29, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 29, 2012	Dec. 31, 2011	Jan. 01, 2011
Schedule Of Quarterly Financial Information [Line Items]
Sales	$ 749,442	$ 717,282	$ 681,561	$ 898,206	$ 653,566	$ 675,369	$ 642,596	$ 801,825	$ 3,046,491	$ 2,773,356	$ 2,573,769
Materials, supplies, labor and other production costs (exclusive of depreciation and amortization shown separately)	390,666	382,508	365,658	478,978	353,350	365,706	341,887	412,258	1,617,810	1,473,201	1,346,790
Net income	$ 38,567	$ 31,231	$ 28,380	$ 37,943	$ 23,038	$ 31,019	$ 28,210	$ 41,161	$ 136,121	$ 123,428	$ 137,047
Basic net income per share	$ 0.28	$ 0.23	$ 0.21	$ 0.28	$ 0.17	$ 0.23	$ 0.21	$ 0.31	$ 1.00	$ 0.91	$ 1.00
Diluted net income per share	$ 0.28	$ 0.22	$ 0.21	$ 0.28	$ 0.17	$ 0.23	$ 0.21	$ 0.30	$ 0.98	$ 0.90	$ 0.99