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		4 Months Ended
		Apr. 22, 2017	Apr. 23, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives	[1]	$ (3,518)	$ 2,588
Production costs		607,941	621,190
Income before income taxes		95,077	92,378
Reclassification out of Accumulated Other Comprehensive Income
Derivative Instruments, Gain (Loss) [Line Items]
Income before income taxes	[2]	474	1,143
Interest Rate Contracts | Reclassification out of Accumulated Other Comprehensive Income
Derivative Instruments, Gain (Loss) [Line Items]
Interest expense (income)	[2]	27	47
Commodity Contract
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives	[1]	(3,518)	2,588
Commodity Contract | Reclassification out of Accumulated Other Comprehensive Income
Derivative Instruments, Gain (Loss) [Line Items]
Production costs	[2],[3]	$ 447	$ 1,096

[1] Amounts in parentheses indicate debits to determine net income.

[2] Amounts in parentheses, if any, indicate credits to determine net income.

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