Equity Investment in Affiliate - Narrative (Details)	3 Months Ended	12 Months Ended
	Sep. 27, 2025 USD ($)	Sep. 27, 2025 USD ($)	Sep. 28, 2024 USD ($)	Sep. 30, 2023 USD ($)	Dec. 07, 2023 USD ($) $ / shares shares	Oct. 14, 2009 manufacturer
Schedule of Equity Method Investments [Line Items]
Number of manufacturers before venture | manufacturer						2
Equity investment in affiliates	$ 35,197,000	$ 35,197,000	$ 32,089,000
Equity in net income of non-consolidated affiliate(s)		2,082,000	11,839,000	$ 6,960,000
Equity investment in affiliate(s) (Note 17)		$ 1,000,000	552,000	0
Micro Bird Holdings, Inc.
Schedule of Equity Method Investments [Line Items]
Equity interest in equity method investment (as a percent)	50.00%	50.00%
Equity investment in affiliates	$ 35,200,000	$ 35,200,000	24,400,000
Equity in net income of non-consolidated affiliate(s)		$ 10,800,000	12,100,000	$ 7,000,000.0
Clean Bus Solutions
Schedule of Equity Method Investments [Line Items]
Equity interest in equity method investment (as a percent)	50.00%	50.00%
Equity investment in affiliates	$ 0	$ 0	7,700,000
Equity in net income of non-consolidated affiliate(s)		(1,300,000)	(300,000)
Initial contribution					$ 10,000,000
Additional contribution					$ 100,000,000
Number of shares called by warrants | shares					1,000,000
Exercise price (dollars per share) | $ / shares					$ 25.00
Equity investment in affiliate(s) (Note 17)		1,000,000	600,000
Dividends		$ 0	$ 0
Non-cash impairment charge	$ 7,400,000
Clean Bus Solutions | Blue Bird
Schedule of Equity Method Investments [Line Items]
Additional contribution					$ 20,000,000
Clean Bus Solutions | Generate Capital
Schedule of Equity Method Investments [Line Items]
Additional contribution					$ 80,000,000