Components of Net Periodic Benefit Cost (Detail) - USD ($) $ in Thousands	4 Months Ended
	Apr. 24, 2021	Apr. 18, 2020
Defined Benefit Plan Disclosure [Line Items]
Settlement and curtailment loss		$ 116,207
Pension plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 299	265
Interest cost	233	1,423
Expected return on plan assets	(575)	(2,689)
Settlement and curtailment loss		116,207
Amortization of prior service cost (credit)	18	75
Amortization of net (gain) loss	229	1,367
Total net periodic pension cost (income)	204	116,648
Postretirement Benefit Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	103	87
Interest cost	36	60
Amortization of prior service cost (credit)	(1)	(1)
Amortization of net (gain) loss	(65)	(92)
Total net periodic pension cost (income)	$ 73	$ 54