Segment Information - Geographic Information (Detail) $ in Millions	3 Months Ended								12 Months Ended
	Sep. 28, 2018 USD ($) country	Jun. 29, 2018 USD ($)	Mar. 30, 2018 USD ($)	Dec. 29, 2017 USD ($)	Sep. 29, 2017 USD ($) country	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 30, 2016 USD ($)	Sep. 28, 2018 USD ($) country	Sep. 29, 2017 USD ($) country	Sep. 30, 2016 USD ($) country
Segment Reporting Information [Line Items]
Revenues	$ 801.6	$ 709.1	$ 729.9	$ 678.5	$ 721.8	$ 632.8	$ 663.2	$ 601.5	$ 2,919.1	$ 2,619.3	$ 2,593.7
Property, plant and equipment, net	274.6				255.3				274.6	255.3
United States
Segment Reporting Information [Line Items]
Revenues									1,308.3	1,222.0	1,167.2
Property, plant and equipment, net	159.5				163.8				159.5	163.8
Other countries
Segment Reporting Information [Line Items]
Revenues									1,610.8	1,397.3	$ 1,426.5
Property, plant and equipment, net	$ 115.1				$ 91.5				$ 115.1	$ 91.5
Revenues | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Number of countries outside the U.S. representing at least 10% | country	0				0				0	0	0
Property, plant and equipment, net | Geographic Concentration Risk
Segment Reporting Information [Line Items]
Number of countries outside the U.S. representing at least 10% | country	0				0				0	0	0