SUPPLEMENTAL BALANCE SHEET INFORMATION - Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Sep. 30, 2025
Accrued Liabilities and Other Liabilities [Abstract]
Accrued compensation	$ 9,375	$ 12,832
Non-income taxes	3,560	3,491
Accrued interest	3,432	4,388
Current portion of long-term finance lease	511	495
Other	8,270	7,516
Accrued expenses and other current liabilities	41,148	44,722
US DOJ Resolution and Plea Agreements
Accrued Liabilities and Other Liabilities [Abstract]
Agreement in Principle	5,000	5,000
Loss contingency, estimate of possible loss	17,000
Securities Class Action Lawsuit
Accrued Liabilities and Other Liabilities [Abstract]
Agreement in Principle	$ 11,000	11,000
Liability recorded related to lawsuits		$ 11,000