Restructuring Charges - Charges Taken Related to Restructuring Actions (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2023	Sep. 24, 2022	Sep. 25, 2021
Restructuring Cost and Reserve [Line Items]
Fiscal restructuring charges			$ 8.7
Fiscal 2021 restructuring charges | Restructuring Charges
Restructuring Cost and Reserve [Line Items]
Workforce reductions			9.3
Fiscal restructuring charges			9.3
Fiscal 2022 restructuring charges | Restructuring Charges
Restructuring Cost and Reserve [Line Items]
Workforce reductions		$ 1.9
Facility closure costs		0.5
Fiscal restructuring charges		2.4
Fiscal 2023 restructuring charges | Restructuring Charges
Restructuring Cost and Reserve [Line Items]
Workforce reductions	$ 11.5
Facility closure costs	0.5
Fiscal restructuring charges	12.0
Fiscal 2023 Actions | Fiscal 2021 restructuring charges | Restructuring Charges
Restructuring Cost and Reserve [Line Items]
Workforce reductions			0.0
Fiscal restructuring charges			0.0
Fiscal 2023 Actions | Fiscal 2022 restructuring charges | Restructuring Charges
Restructuring Cost and Reserve [Line Items]
Workforce reductions		0.0
Facility closure costs		0.0
Fiscal restructuring charges		0.0
Fiscal 2023 Actions | Fiscal 2023 restructuring charges | Restructuring Charges
Restructuring Cost and Reserve [Line Items]
Workforce reductions	5.5
Facility closure costs	0.0
Fiscal restructuring charges	5.5
Fiscal 2022 Actions | Fiscal 2021 restructuring charges | Restructuring Charges
Restructuring Cost and Reserve [Line Items]
Workforce reductions			0.0
Fiscal restructuring charges			0.0
Fiscal 2022 Actions | Fiscal 2022 restructuring charges | Restructuring Charges
Restructuring Cost and Reserve [Line Items]
Workforce reductions		2.6
Facility closure costs		0.5
Fiscal restructuring charges		3.1
Fiscal 2022 Actions | Fiscal 2023 restructuring charges | Restructuring Charges
Restructuring Cost and Reserve [Line Items]
Workforce reductions	6.0
Facility closure costs	0.5
Fiscal restructuring charges	6.5
Fiscal 2021 Actions | Fiscal 2021 restructuring charges | Restructuring Charges
Restructuring Cost and Reserve [Line Items]
Workforce reductions			8.7
Fiscal restructuring charges			8.7
Fiscal 2021 Actions | Fiscal 2022 restructuring charges | Restructuring Charges
Restructuring Cost and Reserve [Line Items]
Workforce reductions		(0.3)
Facility closure costs		0.0
Fiscal restructuring charges		(0.3)
Fiscal 2021 Actions | Fiscal 2023 restructuring charges | Restructuring Charges
Restructuring Cost and Reserve [Line Items]
Workforce reductions	0.0
Facility closure costs	0.0
Fiscal restructuring charges	0.0
Other | Fiscal 2021 restructuring charges | Restructuring Charges
Restructuring Cost and Reserve [Line Items]
Workforce reductions			0.6
Fiscal restructuring charges			$ 0.6
Other | Fiscal 2022 restructuring charges | Restructuring Charges
Restructuring Cost and Reserve [Line Items]
Workforce reductions		(0.4)
Facility closure costs		0.0
Fiscal restructuring charges		$ (0.4)
Other | Fiscal 2023 restructuring charges | Restructuring Charges
Restructuring Cost and Reserve [Line Items]
Workforce reductions	0.0
Facility closure costs	0.0
Fiscal restructuring charges	$ 0.0