Employee Benefit Plans (Tables)

3 Months Ended

Apr. 01, 2018

Retirement Benefits [Abstract]

Components of Net Periodic Benefit Costs

Components of net periodic benefit costs were as follows (in thousands):

	Three months ended
	April 1, 2018			March 26, 2017
Pension and SERPA Benefits
Service cost	$	8,155		$	7,896
Interest cost	20,590			21,269
Expected return on plan assets	(36,891		)	(35,345		)
Amortization of unrecognized:
Prior service (credit) cost	(106		)	254
Net loss	15,819			10,998
Curtailment loss	1,018			—
Net periodic benefit cost	$	8,585		$	5,072
Postretirement Healthcare Benefits
Service cost	$	1,812		$	1,875
Interest cost	2,897			3,412
Expected return on plan assets	(3,541		)	(3,156		)
Amortization of unrecognized:
Prior service credit	(460		)	(543		)
Net loss	454			815
Net periodic benefit cost	$	1,162		$	2,403