Summary of Significant Accounting Policies - Concentration Risk (Details)	3 Months Ended		9 Months Ended
	Jun. 30, 2024 item customer	Jun. 30, 2023 customer	Jun. 30, 2024 item customer	Jun. 30, 2023 customer
Concentration of Credit Risk
Number of banks for maintenance of cash balances | item	2		2
Revenues Net | Customer Concentration Risk
Concentrations
Number of major customers | customer	2	3	1	3
Revenues Net | Customer Concentration Risk | Pilatus Aircraft Ltd ("Pilatus")
Concentrations
Concentration of risk (as a percent)	21.00%	25.00%	26.00%	27.00%
Revenues Net | Customer Concentration Risk | Air Transport Services Group
Concentrations
Concentration of risk (as a percent)		24.00%		18.00%
Revenues Net | Customer Concentration Risk | Textron Aviation, Inc
Concentrations
Concentration of risk (as a percent)	10.00%	10.00%		10.00%
Inventory | Supplier Concentration Risk
Concentrations
Number of major suppliers | item	2		1
Supplier Concentration Risk | Supplier Concentration Risk
Concentrations
Number of major customers | customer		4		4