SUPPLEMENTAL BALANCE SHEET INFORMATION - Other Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Sep. 30, 2025
Loss Contingencies [Line Items]
Long-term client deposits	$ 12,396	$ 12,665
Long-term finance leases	2,297	2,430
Other	479	498
Resolution and Plea Agreements	12,972	12,792
Other long-term liabilities	28,144	28,385
Accrued amount - non-current portion	12,972	$ 12,792
US DOJ Resolution and Plea Agreements
Loss Contingencies [Line Items]
Loss contingency, estimate of possible loss	$ 17,000
Accrual interest rate (percent)	4.18%