Benefit Plans - Reconciliation of Plan Assets Fair Value (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at beginning of year	$ 257,790
Fair value of plan assets at end of year	255,389	$ 257,790
Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at beginning of year	0	0
Employer contributions	2,200	2,205
Plan participants’ contributions	776	752
Benefits paid	(3,042)	(2,994)
Medicare Part D subsidy reimbursement	66	37
Fair value of plan assets at end of year	$ 0	$ 0