AOCI Related to Derivative Transactions (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]
Net change in fair value of derivatives	[1]	$ (8,809)	$ 7,238	$ 1,661	$ 3,720
Closed Contracts
Derivative Instruments, Gain (Loss) [Line Items]
Estimated amount of derivatives to be reclassified in income from AOCI				(230)
Closed Contracts | Commodity price risk derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Estimated amount of derivatives to be reclassified in income from AOCI				(196)
Closed Contracts | Interest rate risk derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Estimated amount of derivatives to be reclassified in income from AOCI				(34)
Expiring in 2018
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives				(597)
Expiring in 2018 | Commodity price risk derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives				(597)
Expiring in 2019
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives				(4,837)
Expiring in 2019 | Commodity price risk derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives				(4,837)
Expiring in 2020
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives				(335)
Expiring in 2020 | Commodity price risk derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives				(335)
Expiring in 2021
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives				(109)
Expiring in 2021 | Commodity price risk derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives				(109)
Closed or Expiring Over Next Four Years
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives				(6,108)
Closed or Expiring Over Next Four Years | Commodity price risk derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives				(6,074)
Closed or Expiring Over Next Four Years | Interest rate risk derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives				$ (34)

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