Summary of Effect of One Percent Point Change in Assumed Health Care Cost (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 30, 2017	Dec. 31, 2016	Jan. 02, 2016
Compensation And Retirement Disclosure [Abstract]
One-Percentage Point Decrease, Effect on total of service and interest cost	$ (47)	$ (58)	$ (65)
One-Percentage Point Decrease, Effect on postretirement benefit obligation	(473)	(427)	(554)
One-Percentage Point Increase, Effect on total of service and interest cost	55	67	76
One-Percentage Point Increase, Effect on postretirement benefit obligation	$ 533	$ 480	$ 626

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- Definition

Amount of decrease in accumulated postretirement benefit obligation from one-percentage-point decrease in assumed health care cost trend rate.

+ References

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

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- Definition

Amount of decrease in service and interest cost components of net periodic postretirement benefit cost from one-percentage-point decrease in assumed health care cost trend rate.

+ References

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- Definition

Amount of increase in accumulated postretirement benefit obligation from one-percentage-point increase in assumed health care cost trend rate.

+ References

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- Definition

Amount of increase in service and interest cost components of net periodic postretirement benefit cost from one-percentage-point increase in assumed health care cost trend rate.

+ References

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