Employee Benefit Plans (Tables)

9 Months Ended

Sep. 27, 2020

Retirement Benefits [Abstract]

Components of net periodic benefit cost

The components of net periodic benefit cost include the following:

	Three Months Ended				Nine Months Ended
	September 27, 2020		September 29, 2019		September 27, 2020		September 29, 2019
Retirement Plans
Service cost	$	881	$	1,006	$	2,966	$	2,909
Interest cost	12,785		13,686		38,015		43,729
Expected return on plan assets	(12,427)		(13,114)		(37,234)		(51,443)
Amortization of prior service cost	245		241		742		671
Amortization of net actuarial loss	7,136		5,993		21,270		24,673
Effect of curtailment loss	—		—		31		—
Effect of settlement loss	—		796		661		2,343
Net periodic benefit cost	$	8,620	$	8,608	$	26,451	$	22,882
Retiree Health and Life Insurance Plans
Service cost	$	89	$	77	$	265	$	229
Interest cost	84		116		249		347
Expected return on plan assets	(92)		(179)		(275)		(535)
Amortization of prior service credit	(70)		(124)		(207)		(371)
Amortization of net actuarial gain	(208)		(205)		(620)		(613)
Net periodic benefit income	$	(197)	$	(315)	$	(588)	$	(943)