Revenue Recognition (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Operating income (loss)	$ 1,297	$ (6,483)
Net income (loss) from continuing operations	(7,278)	(16,001)
Net income (loss) from continuing operations attributable to Cubic	$ (12,995)	$ (19,991)
Diluted income (loss) per share attributable to Cubic	$ (0.41)	$ (0.66)
ASU 2014-09 | ASC 606
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Operating income (loss)	$ 1,338	$ (6,168)
Net income (loss) from continuing operations	1,059	(5,762)
Net income (loss) from continuing operations attributable to Cubic	$ 970	$ (5,762)
Diluted income (loss) per share attributable to Cubic	$ 0.03	$ (0.18)