Postretirement Plans - Additional Information (Detail) - USD ($)				3 Months Ended			4 Months Ended	12 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Oct. 06, 2018	Jul. 14, 2018	Oct. 07, 2017	Apr. 21, 2018	Dec. 29, 2018	Dec. 30, 2017	Dec. 31, 2016	Dec. 31, 2017
Pension and Other Postretirement Benefits Disclosure [Line Items]
Defined benefit plans estimated final non-cash settlement charge								$ 125,000,000
Expected pension cost for fiscal 2019								3,000,000
Expected long-term rate of return on plan assets	5.20%	5.90%	5.90%
Expected company contribution								$ 1,041,000
Postretirement Benefits, minimum years of service for eligibility								10 years
Postretirement Benefits, minimum age for eligibility								55 years
Expense under plans								$ 8,474,000	$ (897,000)	$ 2,238,000
Contribution of pension fund in excess of total contribution								5.00%	5.00%	5.00%
Multiemployer plans, minimum contribution								$ 0
Multiemployer plan, withdrawal obligation						$ 15,200,000			$ 15,223,000
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 plans, increase in withdrawal obligation							$ 2,300,000
Multiemployer plan, withdrawal obligation paid							200,000
Common Stock
Pension and Other Postretirement Benefits Disclosure [Line Items]
Defined benefit plan equity securities included in common stock											2,030,363
Equity securities, amount											$ 39,200,000
Percentage of total plan assets											11.50%
Proceeds from sale of equity securities								$ 41,000,000
Pension plans
Pension and Other Postretirement Benefits Disclosure [Line Items]
Required cash contribution to fully fund under defined benefit plans								(32,238,000)	(53,098,000)
Actual return on plan assets								2,437,000	$ 42,076,000	$ 4,700,000
Amortization from accumulated other comprehensive income into net periodic cost (benefit)								$ 7,500,000
Expected long-term rate of return on plan assets								5.34%	8.00%	8.00%
Contribution of company to company pension plans								$ 40,971,000	$ 1,891,000	$ 1,341,000
Last Fifteen Years
Pension and Other Postretirement Benefits Disclosure [Line Items]
Average annual return on the plan assets								6.90%
Non Qualified Pension Plans
Pension and Other Postretirement Benefits Disclosure [Line Items]
Expected company contribution								$ 300,000
Qualified Pension Plans
Pension and Other Postretirement Benefits Disclosure [Line Items]
Expected company contribution								2,500,000
Postretirement Benefit Plans
Pension and Other Postretirement Benefits Disclosure [Line Items]
Required cash contribution to fully fund under defined benefit plans								(8,194,000)	(7,943,000)
Amortization from accumulated other comprehensive income into net periodic cost (benefit)								(300,000)
Contribution of company to company pension plans								1,308,000	376,000
Expected company contribution								1,000,000
Contributions by participants								823,000	330,000	300,000
Multiemployer Plans
Pension and Other Postretirement Benefits Disclosure [Line Items]
Expense under plans								$ 1,000,000	$ 2,100,000	2,200,000
Red Zone
Pension and Other Postretirement Benefits Disclosure [Line Items]
Percentage of funded under multi employer plans								Less than 65 percent
Yellow Zone
Pension and Other Postretirement Benefits Disclosure [Line Items]
Percentage of funded under multi employer plans								Between 65 and less than 80 percent
Green Zone
Pension and Other Postretirement Benefits Disclosure [Line Items]
Percentage of funded under multi employer plans								At least 80 percent
Plan No. 1
Pension and Other Postretirement Benefits Disclosure [Line Items]
Voluntarily contributions made by an employer				$ 100,000	$ 30,000,000		$ 10,000,000
Expected long-term rate of return on plan assets								5.20%
Percentage of total plan assets								100.00%	100.00%
Plan No. 2
Pension and Other Postretirement Benefits Disclosure [Line Items]
Voluntarily contributions made by an employer				$ 600,000
Expected long-term rate of return on plan assets								7.40%
Required | Pension plans
Pension and Other Postretirement Benefits Disclosure [Line Items]
Contribution of company to company pension plans								$ 271,000	$ 286,000	341,000
Required | Non Qualified Pension Plans
Pension and Other Postretirement Benefits Disclosure [Line Items]
Contribution of company to company pension plans								300,000
Discretionary | Pension plans
Pension and Other Postretirement Benefits Disclosure [Line Items]
Contribution of company to company pension plans								40,700,000	$ 1,605,000	$ 1,000,000
Discretionary | Qualified Pension Plans
Pension and Other Postretirement Benefits Disclosure [Line Items]
Contribution of company to company pension plans								40,700,000
Minimum
Pension and Other Postretirement Benefits Disclosure [Line Items]
Required cash contribution to fully fund under defined benefit plans								$ 5,000,000
Retiree medical coverage provided								3 years
Maximum
Pension and Other Postretirement Benefits Disclosure [Line Items]
Required cash contribution to fully fund under defined benefit plans								$ 35,000,000
Retiree medical coverage provided								5 years