Leases - Rental Equipment (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Sep. 30, 2020
Rental Equipment [Abstract]
Rental equipment, primarily wireless recording equipment	$ 95,665	$ 114,783
Accumulated depreciation and impairment	(53,803)	(60,466)
Rental equipment, net	$ 41,862	$ 54,317