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. 14, 2018	Jul. 15, 2017	Jul. 14, 2018	Jul. 15, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in AOCI on Derivatives(Effective Portion)	[1]	$ (8,809)	$ 7,238	$ 1,661	$ 3,720
Production costs		488,871	468,246	1,113,993	1,076,314
Income before income taxes		49,779	66,888	119,560	161,965
Reclassification out of Accumulated Other Comprehensive Income
Derivative Instruments, Gain (Loss) [Line Items]
Income before income taxes	[2]	126	320	423	794
Interest Rate Contracts | Reclassification out of Accumulated Other Comprehensive Income
Derivative Instruments, Gain (Loss) [Line Items]
Interest expense	[2]	25	20	58	47
Commodity Contract
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in AOCI on Derivatives(Effective Portion)	[1]	(8,809)	7,238	1,661	3,720
Commodity Contract | Reclassification out of Accumulated Other Comprehensive Income
Derivative Instruments, Gain (Loss) [Line Items]
Production costs	[2],[3]	$ 101	$ 300	$ 365	$ 747

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

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

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