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, 2025	Sep. 30, 2024
Disaggregation of Revenue [Line Items]
Net revenue	$ 115,437,000	$ 113,166,000
Equipment Sales [Member] | Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Net revenue	50,980,000	45,786,000
Equipment Sales [Member] | Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Net revenue	30,715,000	34,798,000
Parts and Component Sales [Member]
Disaggregation of Revenue [Line Items]
Net revenue	27,016,000	26,456,000
Freight Revenue [Member]
Disaggregation of Revenue [Line Items]
Net revenue	5,591,000	5,172,000
Other [Member]
Disaggregation of Revenue [Line Items]
Net revenue	$ 1,135,000	$ 954,000