Nature of Operations and Summary of Significant Accounting Policies - Disaggregation of Company's Net Revenue by Major Source (Detail) - USD ($)	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Disaggregation of Revenue [Line Items]
Net revenue	$ 103,479,000	$ 85,278,000
Equipment Sales [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Net revenue	37,572,000	24,093,000
Equipment Sales [Member] | Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Net revenue	36,898,000	36,671,000
Parts and Component Sales [Member]
Disaggregation of Revenue [Line Items]
Net revenue	23,856,000	21,017,000
Freight Revenue [Member]
Disaggregation of Revenue [Line Items]
Net revenue	4,709,000	3,497,000
Other [Member]
Disaggregation of Revenue [Line Items]
Net revenue	$ 444,000	$ 0