Financing receivable, net - Credit Quality Indicators (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Sep. 30, 2023
Financing Receivable, Credit Quality Indicator [Line Items]
2024	$ 655
2023	3,722
2022	4,545
2021	1,560
Total	10,482	$ 12,254
Moderate Risk Rating
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0
2023	2,969
2022	278
2021	0
Total	3,247	3,361
Low Risk Rating
Financing Receivable, Credit Quality Indicator [Line Items]
2024	655
2023	753
2022	4,267
2021	1,560
Total	$ 7,235	$ 8,893