Number of share options (or share units) exercised during the current period.

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Name:	us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

Related Party - Additional Information (Detail) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Sep. 29, 2018	Sep. 30, 2017	Dec. 30, 2017
Ms. Winfrey and her related entities
Related Party Transaction [Line Items]
Related Party Transaction, service provided by related party	$ 157	$ 364	$ 2,145	$ 2,920
Ms. Winfrey
Related Party Transaction [Line Items]
Accounts payable to related parties	$ 125		$ 125		$ 828
Number of shares purchased from related party			954
Stock options exercised			1,405