Basis for Presentation - ASC 606 (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Oct. 01, 2018
Revenue, Initial Application Period Cumulative Effect Transition
Operating income (loss)	$ (566)	$ (11,902)
Net income (loss) from continuing operations	$ (10,614)	$ (11,435)
Diluted earnings per share attributable to Cubic (in dollars per share)	$ (0.23)	$ (0.36)
ASU 2014-09 | ASC 606
Revenue, Initial Application Period Cumulative Effect Transition
Cumulative effect of accounting standard adoption			$ 24,500
Operating income (loss)	$ 3,331
Diluted earnings per share attributable to Cubic (in dollars per share)	$ 0.09
ASU 2014-09 | ASC 606 | Change in Estimates
Revenue, Initial Application Period Cumulative Effect Transition
Operating income (loss)	$ 1,814	$ (929)
Net income (loss) from continuing operations	$ 1,271	$ (736)
Diluted earnings per share attributable to Cubic (in dollars per share)	$ 0.04	$ (0.03)