Components of Net Periodic Benefit (Income) Cost (Detail) - USD ($) $ in Thousands		3 Months Ended					6 Months Ended	12 Months Ended
		Dec. 30, 2017	Oct. 07, 2017	Dec. 31, 2016	Oct. 08, 2016	Jul. 16, 2016	Jul. 15, 2017	Dec. 30, 2017	Dec. 31, 2016	Jan. 02, 2016
Defined Benefit Plan Disclosure [Line Items]
Pension plan settlement loss		$ 1,619	$ 3,030	$ 173	$ 1,832	$ 4,641	$ 0	$ 4,649	$ 6,646
Pension plans
Defined Benefit Plan Disclosure [Line Items]
Service cost								755	830	$ 873
Interest cost								12,852	13,682	18,003
Expected return on plan assets								(25,669)	(26,644)	(29,642)
Pension plan settlement loss								4,649	6,646
Prior service cost (credit)								387	387
Actuarial (gain) loss								6,355	7,294	4,978
Net periodic pension cost (income)								(671)	2,195	(5,788)
Current year actuarial (gain) loss								4,119	8,879	(1,916)
Current year prior service cost (credit)										6,199
Settlement loss								(4,649)	(6,646)
Amortization of prior service (cost) credit								(387)	(387)
Amortization of actuarial gain (loss)								(6,355)	(7,294)	(4,978)
Total recognized in other comprehensive (loss) income								(7,272)	(5,448)	(695)
Total recognized in net periodic benefit cost and other comprehensive (income) loss								(7,943)	(3,253)	(6,483)
Postretirement Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost								256	401	398
Interest cost								227	309	360
Prior service cost (credit)								(212)	(212)	(267)
Actuarial (gain) loss								(497)	(454)	(583)
Net periodic pension cost (income)								(226)	44	(92)
Current year actuarial (gain) loss	[1]							188	(2,354)	(159)
Amortization of prior service (cost) credit								212	212	267
Amortization of actuarial gain (loss)								497	454	583
Total recognized in other comprehensive (loss) income								897	(1,688)	691
Total recognized in net periodic benefit cost and other comprehensive (income) loss								$ 671	$ (1,644)	$ 599

[1] In 2015, includes (gain) loss related to (higher) lower than expected Medicare Part D subsidy receipts.