Postretirement Plans - Additional Information (Detail) - USD ($)	3 Months Ended		4 Months Ended
	Oct. 05, 2019	Oct. 07, 2017	Apr. 20, 2019	Apr. 21, 2018
Pension and Other Postretirement Benefits Disclosure [Line Items]
Defined benefit plans estimated final non-cash settlement charge			$ 125,000,000.0
Settlement loss			0	$ (4,668,000)
Voluntarily contributions made by an employer			0	10,000,000.0
Multiemployer plan, withdrawal obligation		$ 15,200,000
Multiemployer plans, increase in withdrawal obligation				2,300,000
Multiemployer plans transition payments payable			$ 3,100,000
Multiemployer plans payable date			Nov. 03, 2017
Multiemployer plan withdrawal liability of net present value monthly payments period		20 years
Multiemployer plan, withdrawal obligation paid				200,000
401(k) Retirement Savings Plans
Pension and Other Postretirement Benefits Disclosure [Line Items]
Total cost and employer contributions			$ 8,500,000	$ 7,300,000
Scenario, Forecast
Pension and Other Postretirement Benefits Disclosure [Line Items]
Voluntarily contributions made by an employer	$ 2,500,000
Minimum
Pension and Other Postretirement Benefits Disclosure [Line Items]
Required cash contribution to fully fund under defined benefit plans			5,000,000.0
Maximum
Pension and Other Postretirement Benefits Disclosure [Line Items]
Required cash contribution to fully fund under defined benefit plans			$ 35,000,000.0