Income and Other Taxes - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Income tax (expense) benefit	$ (82)	$ 55	$ (208)	$ 41
Effective tax rate on continuing operations	1.90%	0.20%	2.90%	0.10%
Interest and penalties accrued as tax liabilities	$ 600		$ 600		$ 600
Uncertain tax benefit	400		400
Unrecognized tax benefit, to be recognized within next 12 months	$ 1,000		$ 1,000