Postretirement Plans - Additional Information (Detail) - USD ($)	3 Months Ended					6 Months Ended	12 Months Ended
	Dec. 30, 2017	Oct. 07, 2017	Dec. 31, 2016	Oct. 08, 2016	Jul. 16, 2016	Jul. 15, 2017	Dec. 29, 2018	Dec. 30, 2017	Dec. 31, 2016	Jan. 02, 2016	Dec. 31, 2017
Pension and Other Postretirement Benefits Disclosure [Line Items]
Settlement loss	$ (1,619,000)	$ (3,030,000)	$ (173,000)	$ (1,832,000)	$ (4,641,000)	$ 0		$ (4,649,000)	$ (6,646,000)
Expected pension income for fiscal 2018	$ 1,700,000							$ 1,700,000
Expected long-term rate of return on plan assets								8.00%
Percentage of total plan assets	100.00%		100.00%					100.00%	100.00%
Expected company contribution	$ 680,000							$ 680,000
Postretirement Benefits, minimum years of service for eligibility								10 years
Postretirement Benefits, minimum age for eligibility								55 years
Expense under plans								$ (897,000)	$ 2,238,000	$ (5,878,000)
Contribution of pension fund in excess of total contribution								5.00%	5.00%	5.00%
Multiemployer plans, minimum contribution	0							$ 0
Multiemployer plan, withdrawal obligation	15,223,000	$ 15,200,000						15,223,000
Multiemployer plans transition payments payable	3,100,000							$ 3,100,000
Multiemployer plans payable date								Nov. 03, 2017
Multiemployer plan withdrawal liability of net present value monthly payments period		20 years
Minimum
Pension and Other Postretirement Benefits Disclosure [Line Items]
Retiree medical coverage provided								3 years
Maximum
Pension and Other Postretirement Benefits Disclosure [Line Items]
Retiree medical coverage provided								5 years
Common Stock
Pension and Other Postretirement Benefits Disclosure [Line Items]
Defined benefit plan equity securities included in common stock			2,030,363						2,030,363		2,030,363
Equity securities, amount			$ 40,500,000						$ 40,500,000		$ 39,200,000
Percentage of total plan assets			12.10%						12.10%		11.50%
Scenario, Forecast
Pension and Other Postretirement Benefits Disclosure [Line Items]
Expected long-term rate of return on plan assets							6.40%
Pension plans
Pension and Other Postretirement Benefits Disclosure [Line Items]
Settlement loss								$ (4,649,000)	$ (6,646,000)
Actual return on plan assets								42,076,000	$ 4,689,000	$ 6,900,000
Amortization from accumulated other comprehensive income into net periodic cost (benefit)	6,100,000							$ 6,100,000
Expected long-term rate of return on plan assets								8.00%	8.00%	8.00%
Contribution of company to company pension plans								$ 1,891,000	$ 1,341,000	$ 10,436,000
Pension plans | Required
Pension and Other Postretirement Benefits Disclosure [Line Items]
Contribution of company to company pension plans								286,000	341,000	436,000
Pension plans | Discretionary
Pension and Other Postretirement Benefits Disclosure [Line Items]
Contribution of company to company pension plans								$ 1,605,000	1,000,000	10,000,000
Last Fifteen Years
Pension and Other Postretirement Benefits Disclosure [Line Items]
Average annual return on the plan assets								8.50%
Non Qualified Pension Plans
Pension and Other Postretirement Benefits Disclosure [Line Items]
Expected company contribution	300,000							$ 300,000
Non Qualified Pension Plans | Required
Pension and Other Postretirement Benefits Disclosure [Line Items]
Contribution of company to company pension plans								300,000
Qualified Pension Plans
Pension and Other Postretirement Benefits Disclosure [Line Items]
Expected company contribution	0							0
Qualified Pension Plans | Discretionary
Pension and Other Postretirement Benefits Disclosure [Line Items]
Contribution of company to company pension plans								1,600,000
Qualified Pension Plans | Scenario, Forecast
Pension and Other Postretirement Benefits Disclosure [Line Items]
Voluntarily contributions made by an employer							$ 10,000,000
Postretirement Benefit Plans
Pension and Other Postretirement Benefits Disclosure [Line Items]
Amortization from accumulated other comprehensive income into net periodic cost (benefit)	(600,000)							(600,000)
Contribution of company to company pension plans								376,000	841,000
Expected company contribution	700,000							700,000
Contributions by participants	$ 300,000							330,000	284,000	200,000
Multiemployer Plans
Pension and Other Postretirement Benefits Disclosure [Line Items]
Expense under plans								$ 2,100,000	$ 2,200,000	$ 2,100,000
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
Qualified Pension Plan
Pension and Other Postretirement Benefits Disclosure [Line Items]
Voluntarily contributions made by an employer								$ 1,600,000