Goodwill and Intangible Assets - Purchased Intangible Assets (Detail) - USD ($) $ in Millions	9 Months Ended
	Sep. 25, 2020	Dec. 27, 2019
Finite Lived Intangible Assets [Line Items]
Definite lives intangible assets, accumulated amortization	$ (76.6)	$ (61.8)
Definite lives intangible assets, net carrying amount	156.5
Intangible Assets, gross carrying value	242.1	242.1
Intangible Assets, net carrying value	$ 165.5	180.3
Minimum [Member]
Finite Lived Intangible Assets [Line Items]
Total purchased intangible assets, useful life	7 years
Maximum [Member]
Finite Lived Intangible Assets [Line Items]
Total purchased intangible assets, useful life	12 years
Customer Relationships [Member]
Finite Lived Intangible Assets [Line Items]
Definite lives intangible assets, gross carrying amount	$ 119.4	119.4
Definite lives intangible assets, accumulated amortization	(47.9)	(39.8)
Definite lives intangible assets, net carrying amount	$ 71.5	79.6
Customer Relationships [Member] | Minimum [Member]
Finite Lived Intangible Assets [Line Items]
Total purchased intangible assets, useful life	6 years
Customer Relationships [Member] | Maximum [Member]
Finite Lived Intangible Assets [Line Items]
Total purchased intangible assets, useful life	10 years
Trade Name [Member]
Finite Lived Intangible Assets [Line Items]
Definite lives intangible assets, gross carrying amount	$ 27.0	27.0
Definite lives intangible assets, accumulated amortization	(10.8)	(8.1)
Definite lives intangible assets, net carrying amount	$ 16.2	18.9
Trade Name [Member] | Minimum [Member]
Finite Lived Intangible Assets [Line Items]
Total purchased intangible assets, useful life	4 years
Trade Name [Member] | Maximum [Member]
Finite Lived Intangible Assets [Line Items]
Total purchased intangible assets, useful life	6 years
Intellectual Properties/Know-How [Member]
Finite Lived Intangible Assets [Line Items]
Definite lives intangible assets, gross carrying amount	$ 13.9	13.9
Definite lives intangible assets, accumulated amortization	(9.4)	(8.4)
Definite lives intangible assets, net carrying amount	$ 4.5	5.5
Recipes [Member]
Finite Lived Intangible Assets [Line Items]
Total purchased intangible assets, useful life	20 years
Definite lives intangible assets, gross carrying amount	$ 73.2	73.2
Definite lives intangible assets, accumulated amortization	(7.6)	(4.9)
Definite lives intangible assets, net carrying amount	$ 65.6	68.3
Standard Operating Procedures [Member]
Finite Lived Intangible Assets [Line Items]
Total purchased intangible assets, useful life	20 years
Definite lives intangible assets, gross carrying amount	$ 8.6	8.6
Definite lives intangible assets, accumulated amortization	(0.9)	(0.6)
Definite lives intangible assets, net carrying amount	$ 7.7	$ 8.0