Business Combinations - Consideration (Details) - USD ($) $ in Millions	1 Months Ended		12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 29, 2017	Oct. 02, 2015
Business Acquisition [Line Items]
Goodwill	$ 220.0		$ 222.6	$ 208.8
Candela
Business Acquisition [Line Items]
Cash paid	13.0
Net non-cash transferred	21.7
Escrow payable	0.5
Total purchase consideration	$ 35.2
Net assumed liabilities			(1.1)
Finite-lived intangible assets			24.9
Goodwill			11.4
Net assets acquired			$ 35.2
Finite-lived intangible asset, useful life (in years)			6 years 2 months
Software Tools Business
Business Acquisition [Line Items]
Cash paid		$ 27.0
Finite-lived intangible assets		8.3
Indefinite-lived intangible assets — IPR&D		8.8
Goodwill		9.9
Net assets acquired		$ 27.0
Finite-lived intangible asset, useful life (in years)			8 years 3 months 18 days