Leases - Lease Costs (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Operating	$ 970	$ 1,312
Short-term	29	56
Variable	5	20
Sublease income	(95)	(49)
Total lease costs	$ 909	$ 1,339