Summary of Reclassifications Out of AOCI (Detail) - USD ($) $ in Thousands		4 Months Ended
		Apr. 24, 2021	Apr. 18, 2020
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Reclassification from AOCI, Gains and losses on cash flow hedges net of tax		$ (220)	$ (411)
Reclassification From AOCI, Current Period Net Of Tax	[1]	(356)	(88,284)
Derivative Instruments
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Reclassification from AOCI, Gains and losses on cash flow hedges before tax	[1]	(294)	(547)
Reclassification from AOCI, Gains and losses on cash flow hedges tax (expense) benefit	[1]	74	136
Reclassification from AOCI, Gains and losses on cash flow hedges net of tax	[1]	(220)	(411)
Reclassification From AOCI, Current Period Net Of Tax		(220)	(411)
Amortization of defined benefit pension items, prior service costs credits
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Reclassification from AOCI, Current Period, before Tax	[1],[2]	(17)	(74)
Amortization of defined benefit pension items, settlement and curtailment loss
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Reclassification from AOCI, Current Period, before Tax	[1]		(116,207)
Amortization of defined benefit pension items, actuarial losses
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Reclassification from AOCI, Current Period, before Tax	[1],[2]	(164)	(1,275)
Accumulated Defined Benefit Plans Adjustment
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Reclassification from AOCI, Current Period, before Tax	[1]	(181)	(117,556)
Reclassification from AOCI, Current Period, Tax benefit	[1]	45	29,683
Reclassification From AOCI, Current Period Net Of Tax	[1]	(136)	(87,873)
Interest Rate Contracts | Derivative Instruments
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Reclassification from AOCI, Gains and losses on cash flow hedges before tax	[1]	(219)	(44)
Commodity Contract | Derivative Instruments
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Reclassification from AOCI, Gains and losses on cash flow hedges before tax	[1],[3]	(75)	(503)
Reclassification from AOCI, Gains and losses on cash flow hedges tax (expense) benefit		19	126
Reclassification from AOCI, Gains and losses on cash flow hedges net of tax		$ (56)	$ (377)

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

[2] These items are included in the computation of net periodic pension cost and are reported in the other components of net periodic pension and postretirement benefits (credit) expense line item on the Condensed Consolidated Statements of Income.  See Note 17, Postretirement Plans, of Notes to Condensed Consolidated Financial Statements of this Form 10-Q for additional information.

[3] Amounts are presented as an adjustment to reconcile net income to net cash provided by operating activities on the Condensed Consolidated Statements of Cash Flows.