Deferred Compensation Plan - Additional Information (Detail) - USD ($)	12 Months Ended
	Sep. 25, 2021	Sep. 26, 2020	Sep. 28, 2019
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Deferred Compensation Liability, Current and Noncurrent	$ 76,100,000	$ 57,700,000
Nonqualified Deferred Compensation Plan [Member]
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Maximum employee contributions from base salary, percentage	75.00%
Maximum employee contributions from annual bonus, percentage	100.00%
Employee contributions vested, percentage	100.00%
Percent vested annually	33.33%
Compensation expense for the DCP discretionary contributions	$ 3,200,000	3,100,000	$ 2,700,000
Investment in group life insurance contracts	$ 64,300,000	$ 49,300,000
Nonqualified Deferred Compensation Plan [Member] | One Third Annually [Member]
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Contributions, vesting period, years	3 years