Commitments and Contingencies - Additional Information (Detail) shares in Thousands, $ in Millions		1 Months Ended		2 Months Ended	3 Months Ended		12 Months Ended
	Jun. 27, 2014 USD ($)	Sep. 30, 2015 patent	Jun. 30, 2015 tender	Nov. 25, 2015 € / shares	Mar. 28, 2014 USD ($)	Dec. 27, 2013 USD ($)	Oct. 02, 2015 USD ($) installment shares	Sep. 26, 2014 USD ($) shares	Sep. 27, 2013 USD ($)	Jul. 03, 2015 USD ($)
Commitments And Contingencies [Line Items]
Long term accrued product warranty costs							$ 2.0	$ 2.0
Minimum rentals under operating leases fiscal year 2016							22.2
Minimum rentals under operating leases fiscal year 2017							18.4
Minimum rentals under operating leases fiscal year 2018							13.0
Minimum rentals under operating leases fiscal year 2019							9.2
Minimum rentals under operating leases fiscal year 2020							7.3
Operating Leases, Future Minimum Payments, Due Thereafter							20.9
Rental expenses							$ 28.8	$ 28.7	$ 26.0
Common stock, shares outstanding (in shares) | shares							98,070	100,942
Environmental cleanup costs, third-party claim costs, project management costs and legal costs							$ 1.3	$ 1.2	1.0
Amount accrued for environmental remediation expense							1.4
Receivables of past and future environmental-related expenditures							2.1	2.2
Restructuring charges incurred							13.3		$ 6.7
Other Sites
Commitments And Contingencies [Line Items]
Estimated environmental remediation costs, minimum							5.5
Estimated environmental remediation costs, maximum							26.0
Amount accrued for environmental remediation expense							7.4
Site contingency loss best estimate							$ 8.8
Accrual for environmental loss contingencies discount rate (as a percent)							4.00%
Other Sites | Minimum
Commitments And Contingencies [Line Items]
Estimated time frames to resolve contingency related to environmental remediation contingencies (in years)							1 year
Other Sites | Maximum
Commitments And Contingencies [Line Items]
Estimated time frames to resolve contingency related to environmental remediation contingencies (in years)							30 years
Cercla Sites And One Past Facility
Commitments And Contingencies [Line Items]
Estimated environmental remediation costs, minimum							$ 1.4
Estimated environmental remediation costs, maximum							9.9
Amount accrued for environmental remediation expense							$ 1.4
Cercla Sites And One Past Facility | Minimum
Commitments And Contingencies [Line Items]
Estimated time frames to resolve contingency related to environmental remediation contingencies (in years)							1 year
Cercla Sites And One Past Facility | Maximum
Commitments And Contingencies [Line Items]
Estimated time frames to resolve contingency related to environmental remediation contingencies (in years)							30 years
Cercla Sites And One Past Facility
Commitments And Contingencies [Line Items]
Responsibility percentage							33.33%
Mevis | Noncontrolling Interests
Commitments And Contingencies [Line Items]
Common stock, shares outstanding (in shares) | shares							482
Noncontrolling interest (as a percent)							26.50%
Loans Receivable | Notes Receivable
Commitments And Contingencies [Line Items]
Commitment							$ 95.6	0.0
Loans Receivable | Notes Receivable | MPTC loan
Commitments And Contingencies [Line Items]
Number of installments | installment							4
Installment amount										$ 5.7
Commitment							$ 22.8	0.0
Loans Receivable | Notes Receivable | NYPC loan
Commitments And Contingencies [Line Items]
Commitment							$ 72.8	$ 0.0
Subsequent Event | Mevis
Commitments And Contingencies [Line Items]
Annual recurring compensation (in euro per share) | € / shares				€ 0.95
Put right (in euro per share) | € / shares				€ 19.77
Elekta
Commitments And Contingencies [Line Items]
Loss Contingency, Patents Allegedly Infringed, Number | patent		3
Portugal Investigation
Commitments And Contingencies [Line Items]
Number of tenders | tender			3
University of Pittsburgh
Commitments And Contingencies [Line Items]
Losses accrued					$ 25.1	$ 5.0
Settlement amount	$ 35.6
Prepaid royalties	$ 5.5
University of Pittsburgh | Patents
Commitments And Contingencies [Line Items]
Amortization period for intangible assets (in years)							2 years 6 months