Leases - Lease Costs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Leases [Abstract]
Operating	$ 903	$ 834	$ 2,763	$ 3,399
Short-term	18	30	88	133
Variable	40	28	70	51
Sublease income	(46)	(70)	(233)	(198)
Total lease costs	$ 915	$ 822	$ 2,688	$ 3,385