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		6 Months Ended
		Jul. 15, 2017	Jul. 16, 2016	Jul. 15, 2017	Jul. 16, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives	[1]	$ 7,238	$ (3,525)	$ 3,720	$ (937)
Production costs		468,152	477,955	1,076,093	1,099,145
Income before income taxes		66,888	78,425	161,965	170,803
Reclassification out of Accumulated Other Comprehensive Income
Derivative Instruments, Gain (Loss) [Line Items]
Income before income taxes	[2]	320	803	794	1,946
Interest Rate Contracts | Reclassification out of Accumulated Other Comprehensive Income
Derivative Instruments, Gain (Loss) [Line Items]
Interest expense	[2]	20	35	47	82
Commodity Contract
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives	[1]	7,238	(3,525)	3,720	(937)
Commodity Contract | Reclassification out of Accumulated Other Comprehensive Income
Derivative Instruments, Gain (Loss) [Line Items]
Production costs	[2],[3]	$ 300	$ 768	$ 747	$ 1,864

[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).