Effect of Derivative Instruments for Deferred Gains And (Losses) on Closed Contracts and Effective Portion in Fair Value on AOCI, Utilized for Risk Management Purposes (Detail) - USD ($) $ in Thousands		3 Months Ended						4 Months Ended		12 Months Ended
		Dec. 31, 2016	Oct. 08, 2016	Jul. 16, 2016	Jan. 02, 2016	Oct. 10, 2015	Jul. 18, 2015	Apr. 23, 2016	Apr. 25, 2015	Dec. 31, 2016	Jan. 02, 2016	Jan. 03, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives										$ 5,730	$ (4,195)	$ (3,358)
Production costs		$ 450,462	$ 476,760	$ 477,955	$ 455,939	$ 464,045	$ 457,253	$ 621,190	$ 585,916	2,026,367	1,963,153	1,950,633
Income before income taxes										249,537	293,031	268,054
Reclassification out of Accumulated Other Comprehensive Income
Derivative Instruments, Gain (Loss) [Line Items]
Income before income taxes										3,399	5,413	3,366
Interest Rate Contracts
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives										666
Interest Rate Contracts | Reclassification out of Accumulated Other Comprehensive Income
Derivative Instruments, Gain (Loss) [Line Items]
Interest expense (income)										135	154	157
Commodity Contract
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives										5,064	(4,195)	(3,358)
Commodity Contract | Reclassification out of Accumulated Other Comprehensive Income
Derivative Instruments, Gain (Loss) [Line Items]
Production costs	[1]									$ 3,264	$ 5,259	$ 3,209

[1] Included in Materials, supplies, labor and other production costs (exclusive of depreciation and amortization shown separately).