LEASES - Right-of-use lease assets and lease liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Sep. 30, 2022
Right-of-use lease assets and lease liabilities
Operating ROU assets, net	$ 41,426	$ 32,489
Current portion of operating lease liabilities	10,755	7,982
Long-term operating lease liabilities	31,795	24,854
Total lease liability	42,550	32,836
Finance ROU assets, net	47	79
Current portion of finance lease liabilities	31	43
Long-term finance lease liabilities	19	41
Total lease liability	$ 50	$ 84
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other Assets, Noncurrent	Other Assets, Noncurrent
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Accrued Liabilities, Current	Accrued Liabilities, Current
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other long-term liabilities	Other long-term liabilities