Pensions and Other Post-employment Benefits (Detail 1) - USD ($) $ in Thousands	9 Months Ended
	Sep. 25, 2020	Sep. 27, 2019
Defined Benefit Plan Disclosure
Pension curtailment charge	$ (94)	$ (3,296)
Pension Benefits
Defined Benefit Plan Disclosure
Contributions by employer	0	4,500
Pension curtailment charge	$ (94)	$ (3,296)