Accumulated Other Comprehensive Loss Related to Derivative Transactions (Detail) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jul. 16, 2016	Jul. 18, 2015	Jul. 16, 2016	Jul. 18, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives	[1]	$ (3,525)	$ 5,818	$ (937)	$ 1,390
Closed Contracts
Derivative Instruments, Gain (Loss) [Line Items]
Estimated amount of derivatives to be reclassified in income from AOCI				1,202
Closed Contracts | Commodity price risk derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Estimated amount of derivatives to be reclassified in income from AOCI				320
Closed Contracts | Interest rate risk derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Estimated amount of derivatives to be reclassified in income from AOCI				882
Expiring in 2016
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives				5,597
Expiring in 2016 | Commodity price risk derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives				5,597
Expiring in 2017
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives				2,382
Expiring in 2017 | Commodity price risk derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives				2,382
Closed or Expiring Over Next Three Years
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives				9,181
Closed or Expiring Over Next Three Years | Commodity price risk derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives				8,299
Closed or Expiring Over Next Three Years | Interest rate risk derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Net change in fair value of derivatives				$ 882

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