Employee Benefit Plans (Tables)

3 Months Ended

Mar. 26, 2017

Compensation and Retirement Disclosure [Abstract]

Components of Net Periodic Benefit Costs

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

	Three months ended
	March 26, 2017			March 27, 2016
Pension and SERPA Benefits
Service cost	$	7,896		$	8,359
Interest cost	21,269			22,707
Expected return on plan assets	(35,345		)	(36,445		)
Amortization of unrecognized:
Prior service cost	254			255
Net loss	10,998			11,587
Settlement loss	—			300
Net periodic benefit cost	$	5,072		$	6,763
Postretirement Healthcare Benefits
Service cost	$	1,875		$	1,870
Interest cost	3,412			3,704
Expected return on plan assets	(3,156		)	(3,017		)
Amortization of unrecognized:
Prior service credit	(543		)	(701		)
Net loss	815			884
Net periodic benefit cost	$	2,403		$	2,740