Accumulated Other Comprehensive Loss (Income) Related to Derivative Transactions (Detail) - USD ($) $ in Thousands		4 Months Ended
		Apr. 18, 2020	Apr. 20, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives	[1]	$ (3,849)	$ (9,593)
Closed Contracts
Derivative Instruments, Gain (Loss) [Line Items]
Estimated amount of derivatives to be reclassified in income from AOCI		(123)
Closed Contracts | Commodity price risk derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Estimated amount of derivatives to be reclassified in income from AOCI		(278)
Closed Contracts | Interest rate risk derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Estimated amount of derivatives to be reclassified in income from AOCI		155
Expiring in 2020
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives		(1,620)
Expiring in 2020 | Commodity price risk derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives		(1,620)
Expiring in 2021
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives		169
Expiring in 2021 | Commodity price risk derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives		169
Expiring in 2022
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives		(206)
Expiring in 2022 | Commodity price risk derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives		(206)
Closed or Expiring Over Next Four Years
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives		(1,780)
Closed or Expiring Over Next Four Years | Commodity price risk derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives		(1,935)
Closed or Expiring Over Next Four Years | Interest rate risk derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives		$ 155

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