Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Oct. 01, 2022	Oct. 02, 2021	Oct. 03, 2020
Disaggregation of Revenue [Line Items]
Net sales	$ 800,637	$ 683,995	$ 879,221
Diesel buses
Disaggregation of Revenue [Line Items]
Net sales	276,395	291,203	397,567
Alternative fuel buses
Disaggregation of Revenue [Line Items]
Net sales	407,599	300,706	381,555
Other
Disaggregation of Revenue [Line Items]
Net sales	41,858	34,875	45,191
Parts
Disaggregation of Revenue [Line Items]
Net sales	$ 74,785	$ 57,211	$ 54,908