Components of Net Periodic Benefit (Income) Cost (Detail) - USD ($) $ in Thousands	3 Months Ended		4 Months Ended	6 Months Ended
	Jul. 14, 2018	Jul. 15, 2017	Apr. 21, 2018	Jul. 14, 2018	Jul. 15, 2017
Defined Benefit Plan Disclosure [Line Items]
Settlement loss	$ 1,035		$ 4,668	$ 5,703
Pension plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	216	$ 174		504	$ 407
Interest cost	3,123	3,006		6,247	7,013
Expected return on plan assets	(4,678)	(5,895)		(10,085)	(13,754)
Settlement loss	1,035			5,703
Amortization of prior service cost (credit)	95	89		195	208
Amortization of net (gain) loss	1,256	1,469		2,829	3,427
Total net periodic pension cost (income)	1,047	(1,157)		5,393	(2,699)
Postretirement Benefit Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	66	59		155	138
Interest cost	54	52		127	122
Amortization of prior service cost (credit)	(49)	(49)		(114)	(114)
Amortization of net (gain) loss	(99)	(114)		(232)	(268)
Total net periodic pension cost (income)	$ (28)	$ (52)		$ (64)	$ (122)