Retirement Plans (Tables)

3 Months Ended

Mar. 31, 2018

Compensation And Retirement Disclosure [Abstract]

Components of Net Periodic Benefit (Credits) Costs for Pension and Other Postretirement Benefits

The components of net periodic benefit (credits) costs for pension and other postretirement benefits, for Company sponsored plans, are provided below (in thousands):

	13-Weeks Ended
	Pension Benefits						Other Postretirement Plans
	March 31, 2018			April 1, 2017			March 31, 2018			April 1, 2017
Components of net periodic benefit (credits) costs
Service cost	$	573		$	506		$	9		$	10
Interest cost		8,781			10,138			59			72
Expected return on plan assets		(12,780	)		(11,964	)		—			—
Amortization of prior service cost		1			35			2			1
Amortization of net loss (gain)		846			1,051			(39	)		(13	)
Net periodic benefit (credits) costs	$	(2,579	)	$	(234	)	$	31		$	70