Leases - Supplemental Balance Sheet (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Sep. 30, 2020
Assets and Liabilities, Lessee [Abstract]
Operating lease other non-current asset	$ 16,342	$ 14,334
Total lease assets	16,342	14,334
Operating lease other current liabilities	2,680	2,527
Operating lease other non-current liability	19,072	16,193
Total lease liabilities	$ 21,752	$ 18,720