Segment Information (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Jul. 02, 2022 USD ($)	Jul. 03, 2021 USD ($)	Jul. 02, 2022 USD ($) segment	Jul. 03, 2021 USD ($)
Segment Reporting Information [Line Items]
Number of Operating Segments | segment			2
Net sales	$ 206,083	$ 196,659	$ 542,965	$ 491,791
Gross profit	21,593	26,159	40,947	59,120
United States
Segment Reporting Information [Line Items]
Net sales	193,571	179,850	488,363	436,286
Canada
Segment Reporting Information [Line Items]
Net sales	12,009	15,072	50,506	49,257
Rest of world
Segment Reporting Information [Line Items]
Net sales	503	1,737	4,096	6,248
Operating Segments
Segment Reporting Information [Line Items]
Gross profit	21,593	26,159	40,947	59,120
Operating Segments | Bus
Segment Reporting Information [Line Items]
Net sales	186,631	181,735	487,552	449,876
Gross profit	13,632	20,471	19,290	43,265
Operating Segments | Parts
Segment Reporting Information [Line Items]
Net sales	19,452	14,924	55,413	41,915
Gross profit	7,961	5,688	21,657	15,855
Intersegment Eliminations | Parts
Segment Reporting Information [Line Items]
Net sales	$ 700	$ 900	$ 2,600	$ 2,900