Pension and Other Employee Benefits - Additional Information (Detail) - USD ($) $ in Millions	Sep. 26, 2020	Sep. 28, 2019
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit pension plan, liabilities	$ (10.9)	$ (10.0)
Accumulated benefit obligation	(10.9)	(10.0)
Projected benefit obligation for long-term service awards	0.1	0.1
Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Projected benefit obligation in excess of plan assets	$ (10.9)	$ (10.0)

Projected Benefit Obligation For Long Term Service Awards

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- Definition

Amount of liability, recognized in statement of financial position, for defined benefit pension plan. Excludes other postretirement benefit plan.

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Amount of accumulated benefit obligation for defined benefit plan with accumulated benefit obligation in excess of plan assets.

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Amount of projected benefit obligation for defined benefit pension plan with accumulated benefit obligation in excess of plan assets.

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