Components of Net Periodic Benefit (Income) Cost (Detail) - USD ($) $ in Thousands	3 Months Ended			4 Months Ended	9 Months Ended
	Oct. 06, 2018	Jul. 14, 2018	Oct. 07, 2017	Apr. 21, 2018	Oct. 06, 2018	Oct. 07, 2017
Defined Benefit Plan Disclosure [Line Items]
Settlement loss	$ 930	$ 1,035	$ 3,030	$ 4,668	$ 6,633	$ 3,030
Pension plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	216		174		720	581
Interest cost	3,166		2,779		9,413	9,792
Expected return on plan assets	(4,464)		(5,437)		(14,549)	(19,191)
Settlement loss	930		3,030		6,633	3,030
Amortization of prior service cost (credit)	97		83		291	291
Amortization of net (gain) loss	1,126		1,365		3,956	4,792
Total net periodic pension cost (income)	1,071		1,994		6,464	(705)
Postretirement Benefit Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	66		59		221	197
Interest cost	54		52		181	174
Amortization of prior service cost (credit)	(49)		(49)		(163)	(163)
Amortization of net (gain) loss	(99)		(114)		(331)	(383)
Total net periodic pension cost (income)	$ (28)		$ (52)		$ (92)	$ (175)