Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net (loss) income	$ (15,723)	$ (5,162)	$ 5,305
Foreign currency translation adjustment	1,790	(1,746)	(1,445)
Reclassification adjustment for net foreign currency translation losses included in net (loss) income	8,797	487
Comprehensive (loss) income	$ (5,136)	$ (6,421)	$ 3,860