Balance Sheet Components - Components of Property, Plant and Equipment (Detail) - USD ($) $ in Millions	Sep. 28, 2018	Sep. 29, 2017
Balance Sheet Related Disclosures [Abstract]
Land and land improvements	$ 44.2	$ 44.2
Buildings and leasehold improvements	227.0	220.4
Machinery and equipment	404.0	375.9
Construction in progress	28.6	14.6
Property, plant and equipment:	703.8	655.1
Accumulated depreciation and amortization	(429.2)	(399.8)
Total property, plant and equipment, net	$ 274.6	$ 255.3

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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Amount before accumulated depreciation of building structures held for productive use including addition, improvement, or renovation to the structure, including, but not limited to, interior masonry, interior flooring, electrical, and plumbing.

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Amount of structure or a modification to a structure under construction. Includes recently completed structures or modifications to structures that have not been placed into service.

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Amount before accumulated deprecation and depletion of real estate held for productive use and additions or improvements to real estate held for productive use, examples include, but are not limited to, walkways, driveways, fences, and parking lots. Excludes land held for sale.

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Amount before accumulated depreciation of tangible personal property used to produce goods and services, including, but is not limited to, tools, dies and molds, computer and office equipment.

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Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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