AOCI Related to Derivative Transactions (Detail) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Oct. 06, 2018	Oct. 07, 2017	Oct. 06, 2018	Oct. 07, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives	[1]	$ 7,394	$ (9,652)	$ 9,055	$ (5,932)
Closed Contracts
Derivative Instruments, Gain (Loss) [Line Items]
Estimated amount of derivatives to be reclassified in income from AOCI				(462)
Closed Contracts | Commodity price risk derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Estimated amount of derivatives to be reclassified in income from AOCI				(453)
Closed Contracts | Interest rate risk derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Estimated amount of derivatives to be reclassified in income from AOCI				(9)
Expiring in 2018
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives				29
Expiring in 2018 | Commodity price risk derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives				29
Expiring in 2019
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives				2,073
Expiring in 2019 | Commodity price risk derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives				2,073
Expiring in 2020
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives				32
Expiring in 2020 | Commodity price risk derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives				32
Expiring in 2021
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives				(120)
Expiring in 2021 | Commodity price risk derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives				(120)
Closed or Expiring Over Next Four Years
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives				1,552
Closed or Expiring Over Next Four Years | Commodity price risk derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives				1,561
Closed or Expiring Over Next Four Years | Interest rate risk derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives				$ (9)

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