Revenue Recognition (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Operating income (loss)	$ (6,483)	$ (566)
Net income (loss) from continuing operations	$ (16,001)	$ (10,614)
Diluted earnings per share attributable to Cubic (in dollars per share)	$ (0.66)	$ (0.23)
ASU 2014-09 | Adjustments | ASC 606
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Operating income (loss)	$ (6,168)	$ 1,814
Net income (loss) from continuing operations	$ (5,762)	$ 1,271
Diluted earnings per share attributable to Cubic (in dollars per share)	$ (0.18)	$ 0.04