Employee Benefit Plans (Tables)

6 Months Ended

Jun. 28, 2020

Retirement Benefits [Abstract]

Components of net periodic benefit cost

The components of net periodic benefit cost include the following:

	Three Months Ended				Six Months Ended
	June 28, 2020		June 30, 2019		June 28, 2020		June 30, 2019
Retirement Plans
Service cost	$	1,003	$	962	$	2,085	$	1,903
Interest cost	12,549		15,100		25,230		30,043
Expected return on plan assets	(12,227)		(19,232)		(24,807)		(38,329)
Amortization of prior service cost	247		216		497		430
Amortization of net actuarial loss	7,258		9,646		14,134		18,680
Effect of curtailment loss	31		—		31		—
Effect of settlement loss	38		225		661		1,547
Net periodic benefit cost	$	8,899	$	6,917	$	17,831	$	14,274
Retiree Health and Life Insurance Plans
Service cost	$	93	$	78	$	176	$	152
Interest cost	81		113		165		231
Expected return on plan assets	(93)		(179)		(183)		(356)
Amortization of prior service credit	(69)		(124)		(137)		(247)
Amortization of net actuarial gain	(215)		(215)		(412)		(408)
Net periodic benefit income	$	(203)	$	(327)	$	(391)	$	(628)