Postretirement Plans - Additional Information (Detail) - USD ($)			3 Months Ended	4 Months Ended
	Dec. 29, 2018	Mar. 31, 2018	Oct. 07, 2017	Apr. 21, 2018	Apr. 22, 2017	Dec. 30, 2017
Pension and Other Postretirement Benefits Disclosure [Line Items]
Pension plan settlement loss				$ 4,668,000
Expected long-term rate of return on plan assets		6.40%
Total cost and employer contributions				7,300,000	$ 9,000,000
Multiemployer plan, withdrawal obligation			$ 15,200,000	17,337,000		$ 15,223,000
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
Qualified Pension Plan
Pension and Other Postretirement Benefits Disclosure [Line Items]
Voluntarily contributions made by an employer				$ 10,000,000
Scenario, Forecast
Pension and Other Postretirement Benefits Disclosure [Line Items]
Expected long-term rate of return on plan assets	5.90%