Benefit Plans - Funded Status, Postretirement Benefits (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 29, 2019
Defined Benefit Plan Disclosure [Line Items]
Noncurrent liabilities	$ (113,325)	$ (114,831)
Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Current liabilities	(2,886)	(2,831)
Noncurrent liabilities	(64,779)	(59,225)
Total liability - pension plans	$ (67,665)	$ (62,056)