Segment Information - Geographic Information (Detail) $ in Millions	3 Months Ended								12 Months Ended
	Sep. 27, 2019 USD ($) country	Jun. 28, 2019 USD ($)	Mar. 29, 2019 USD ($)	Dec. 28, 2018 USD ($)	Sep. 28, 2018 USD ($) country	Jun. 29, 2018 USD ($)	Mar. 30, 2018 USD ($)	Dec. 29, 2017 USD ($)	Sep. 27, 2019 USD ($) country	Sep. 28, 2018 USD ($) country	Sep. 29, 2017 USD ($) country
Segment Reporting Information [Line Items]
Revenues	$ 878.9	$ 825.8	$ 779.4	$ 741.0	$ 801.6	$ 709.1	$ 729.9	$ 678.5	$ 3,225.1	$ 2,919.1	$ 2,619.3
Property, plant and equipment, net	311.5				274.6				311.5	274.6
United States
Segment Reporting Information [Line Items]
Revenues									1,384.3	1,308.3	1,222.0
Property, plant and equipment, net	155.3				159.5				155.3	159.5
Other countries
Segment Reporting Information [Line Items]
Revenues									1,840.8	1,610.8	$ 1,397.3
Property, plant and equipment, net	$ 156.2				$ 115.1				$ 156.2	$ 115.1
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
Property, plant and equipment, net | Geographic Concentration Risk | India
Segment Reporting Information [Line Items]
Concentration risk (percent)									12.00%