Benefit Plans - Reconciliation of Benefit Obligation (Detail) - Postretirement Benefits - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 29, 2019	Dec. 30, 2018
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Beginning balance - projected benefit obligation	$ 62,056	$ 64,461
Service cost	1,454	1,496	$ 1,854
Interest cost	2,031	2,750	2,694
Plan participants’ contributions	753	750
Actuarial (gain) loss	4,555	(4,191)
Benefits paid	(3,184)	(3,296)
Medicare Part D subsidy reimbursement	0	86
Ending balance - projected benefit obligation	$ 67,665	$ 62,056	$ 64,461