Benefit Plans - Reconciliation of Amounts in Accumulated Other Comprehensive Loss That Have Not Yet Been Recognized as Components of Net Periodic Benefit Cost (Detail) $ in Thousands	12 Months Ended
Dec. 29, 2019 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Actuarial gain (loss)	$ (26,663)
Reclassification Adjustments, Actuarial loss	3,147
Net periodic benefit cost, beginning balance	(133,008)
Net periodic benefit cost, ending balance	(156,524)
Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss, beginning balance	(119,595)
Actuarial gain (loss)	(30,855)
Reclassification Adjustments, Actuarial loss	3,688
Actuarial loss, ending balance	(146,762)
Prior service (cost) credits, beginning balance	(48)
Reclassification Adjustments, Prior service (cost) credits	22
Prior service (cost) credits, ending balance	(26)
Postretirement Medical [Member]
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss, beginning balance	(14,658)
Actuarial gain (loss)	4,192
Reclassification Adjustments, Actuarial loss	730
Actuarial loss, ending balance	(9,736)
Prior service (cost) credits, beginning balance	1,293
Reclassification Adjustments, Prior service (cost) credits	$ (1,293)

Amount, before tax, of accumulated other comprehensive (income) loss for defined benefit plan, that has not been recognized in net periodic benefit cost (credit).

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Amount, before tax, of accumulated other comprehensive income (loss) for gain (loss) of defined benefit plan, that has not been recognized in net periodic benefit (cost) credit.

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Amount, before tax, of accumulated other comprehensive (income) loss for cost (credit) of benefit change attributable to participants' prior service from plan amendment or plan initiation of defined benefit plan, that has not been recognized in net periodic benefit cost (credit).

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount, before tax, of reclassification adjustment from accumulated other comprehensive (income) loss for prior service cost (credit) of defined benefit plan.

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Amount, before tax, of gain (loss) for (increase) decrease in value of benefit obligation for change in actuarial assumptions and increase (decrease) in value of plan assets from experience different from that assumed of defined benefit plan, that has not been recognized in net periodic benefit (cost) credit.

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Amount, before tax, of reclassification adjustment from accumulated other comprehensive income (loss) for gain (loss) of defined benefit plan.

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