Components of Net Periodic Benefit (Income) Cost (Detail) - USD ($) $ in Thousands	4 Months Ended
	Apr. 23, 2016	Apr. 25, 2015
Pension plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 255	$ 269
Interest cost	4,532	5,539
Expected return on plan assets	(8,612)	(9,121)
Amortization of prior service cost (credit)	119
Amortization of net (gain) loss	1,798	1,532
Total net periodic benefit (income) cost	(1,908)	(1,781)
Post-retirement Benefit Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	123	122
Interest cost	95	112
Amortization of prior service cost (credit)	(65)	(144)
Amortization of net (gain) loss	(140)	(180)
Total net periodic benefit (income) cost	$ 13	$ (90)