Income Taxes - Foreign and Domestic Income Components (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Domestic	$ (31,989)	$ (9,609)	$ 28,645
Foreign	(38,106)	13,783	26,894
Income from continuing operations before income taxes	$ (70,095)	$ 4,174	$ 55,539