Retirement Benefits (Tables)

3 Months Ended

Mar. 25, 2016

Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]

Components of net periodic benefit cost

The components of net periodic benefit cost for retirement benefit plans were as follows (in thousands):

	Thirteen Weeks Ended
	March 25, 2016			March 27, 2015
Pension Benefits
Service cost	$	1,997		$	2,096
Interest cost	4,017			3,775
Expected return on assets	(4,637		)	(4,917		)
Amortization and other	2,300			2,353
Net periodic benefit cost	$	3,677		$	3,307

Postretirement Medical
Service cost	$	150		$	150
Interest cost	262			226
Amortization	(138		)	(101		)
Net periodic benefit cost	$	274		$	275