Property and Equipment (Detail) - USD ($) $ in Millions	12 Months Ended
	Oct. 01, 2017	Oct. 02, 2016	Sep. 27, 2015
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 612.7	$ 548.0
Accumulated depreciation	(427.8)	(382.2)
Land	1.5	1.5
Construction in progress	11.2	7.6
Property and equipment, net	$ 197.6	174.9	$ 152.7
Property plant and equipment useful life	Shorter of asset life or life of lease
Depreciation expense	$ 48.7	46.1	$ 36.2
Buildings
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	41.8	37.2
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	498.8	439.3
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	9.0	8.9
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 63.1	$ 62.6
Property plant and equipment useful life	Shorter of asset life or life of lease
Minimum | Buildings
Property, Plant and Equipment [Line Items]
Property plant and equipment useful life	20 years
Minimum | Machinery and equipment
Property, Plant and Equipment [Line Items]
Property plant and equipment useful life	3 years
Minimum | Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property plant and equipment useful life	5 years
Maximum | Buildings
Property, Plant and Equipment [Line Items]
Property plant and equipment useful life	40 years
Maximum | Machinery and equipment
Property, Plant and Equipment [Line Items]
Property plant and equipment useful life	10 years
Maximum | Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property plant and equipment useful life	10 years