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Amount of contribution received by defined benefit plan from employer which increases plan assets.

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Retirement Plans - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Oct. 02, 2020	Sep. 27, 2019	Sep. 28, 2018
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total retirement, post-retirement benefit plan and defined benefit plan expense	$ 35.8	$ 33.2	$ 30.2
Accumulated benefit obligation for defined benefit pension plans	255.2	232.3
Contributions by employer	10.6	$ 8.7	$ 9.0
Expected total contribution to the defined benefit plans for the next year	$ 13.4
Equity Securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target percentage allocation	23.00%
Debt and fixed income assets
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target percentage allocation	49.00%
Real Estate
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target percentage allocation	16.00%
Other
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target percentage allocation	12.00%
Minimum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	0.20%
Rate of projected compensation increase (as a percent)	1.75%
Maximum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	1.70%
Rate of projected compensation increase (as a percent)	3.50%
Defined Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	0.68%	0.63%
Rate of projected compensation increase (as a percent)	2.25%	2.27%
Contributions by employer	$ 10.6	$ 8.7
Defined Benefit Plans \| United States
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Maximum eligible participant compensation that company matches under defined contribution plan (as a percent)	6.00%
Defined Benefit Plans \| United States \| Minimum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined contribution plan, annual contributions per employee (percent)	1.00%
Defined Benefit Plans \| United States \| Maximum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined contribution plan, annual contributions per employee (percent)	50.00%
Contribution as percentage on after-tax basis (as a percent)	15.00%
Defined Benefit Plans \| U.K. Savings Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Maximum eligible participant compensation that company matches under defined contribution plan (as a percent)	6.00%
Defined Benefit Plans \| U.K. Savings Plan \| Minimum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined contribution plan, annual contributions per employee (percent)	4.00%
Defined Benefit Plans \| U.K. Savings Plan \| Maximum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined contribution plan, annual contributions per employee (percent)	100.00%