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Franchise Rights Acquired, Goodwill and Other Intangible Assets - Change in Carrying Amount of Goodwill (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 27, 2020	Jun. 29, 2019	Jun. 27, 2020	Jun. 29, 2019
Goodwill [Line Items]
Beginning balance			$ 157,916
Goodwill impairment	$ 0	$ 0	(3,665)	$ 0
Ending balance	151,624		151,624
Kurbo Health, Inc.
Goodwill [Line Items]
Beginning balance			157,916
Goodwill impairment			(3,665)
Effect of exchange rate changes			(2,627)
Ending balance	151,624		151,624
Kurbo Health, Inc. \| North America
Goodwill [Line Items]
Beginning balance			143,940
Goodwill impairment			0
Effect of exchange rate changes			(1,817)
Ending balance	142,123		142,123
Kurbo Health, Inc. \| Continental Europe
Goodwill [Line Items]
Beginning balance			7,015
Goodwill impairment			0
Effect of exchange rate changes			15
Ending balance	7,030		7,030
Kurbo Health, Inc. \| United Kingdom
Goodwill [Line Items]
Beginning balance			1,213
Goodwill impairment			0
Effect of exchange rate changes			(69)
Ending balance	1,144		1,144
Kurbo Health, Inc. \| Other
Goodwill [Line Items]
Beginning balance			5,748
Goodwill impairment			(3,665)
Effect of exchange rate changes			(756)
Ending balance	$ 1,327		$ 1,327