Postretirement Plans - Additional Information (Detail) - USD ($)	3 Months Ended	4 Months Ended
	Oct. 03, 2020	Apr. 18, 2020	Apr. 20, 2019	Mar. 31, 2020
Plan No. 1
Pension and Other Postretirement Benefits Disclosure [Line Items]
Defined benefit plan assets, transferred		$ 6,400,000
Voluntarily contributions made by an employer		1,400,000	$ 0
Defined benefit plan, loan issued		5,000,000.0		$ 5,000,000.0
Defined benefit plans non-cash settlement charge		116,200,000
Settlement loss		111,900,000	0
Defined benefit plan obligation, curtailment loss		4,300,000
Plan No. 2 | Scenario Forecast
Pension and Other Postretirement Benefits Disclosure [Line Items]
Voluntarily contributions made by an employer	$ 2,500,000
401(k) Retirement Savings Plans
Pension and Other Postretirement Benefits Disclosure [Line Items]
Total cost and employer contributions		$ 8,600,000	$ 8,500,000