Post-Retirement Plans - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jul. 15, 2017	Jul. 16, 2016	Jul. 15, 2017	Jul. 16, 2016
Compensation And Retirement Disclosure [Abstract]
Settlement charge		$ (4,641)	$ 0	$ (4,641)
Total cost and employer contributions	$ 6,600	$ 6,500	$ 15,600	$ 14,800

Amount of gain (loss) recognized in net periodic benefit (cost) credit from irrevocable action relieving primary responsibility for benefit obligation and eliminating risk related to obligation and assets used to effect settlement.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (h)(7)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

Name:	us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration