WARRANTY LIABILITY - Summary of changes in warrant liability included in accrued liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Movement in Standard Product Warranty Accrual [Roll Forward]
Balance, beginning of period	$ 7,818	$ 6,268
Warranties issued and changes in estimated pre-existing warranties	19,028	15,560
Actual warranty costs incurred	(16,413)	(14,010)
Other warranty liabilities assumed from acquisitions	6,353	0
Balance, end of period	$ 16,786	$ 7,818