Revenue Recognition (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Operating income (loss)	$ 24,706	$ 34,725	$ (11,711)	$ 27,618
Net income (loss) from continuing operations	7,962	20,546	(60,469)	502
Net income (loss) from continuing operations attributable to Cubic	$ (1,407)	$ 24,112	$ (60,650)	$ 9,472
Diluted earnings per share attributable to Cubic (in dollars per share)	$ (0.04)	$ 0.77	$ (1.94)	$ 0.26
Increase in operating income	$ 25,000		$ 25,000
Increase in net income from continuing operations	$ 27,800		$ 27,800
OpCo.
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Ownership percentage	10.00%		10.00%
ASU 2014-09 | Adjustments | ASC 606
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Operating income (loss)	$ 19,297	$ (1,054)	$ 5,499	$ (1,040)
Net income (loss) from continuing operations	18,596	(1,185)	5,103	(1,100)
Net income (loss) from continuing operations attributable to Cubic	$ 4,826	$ (1,185)	$ (8,667)	$ (1,100)
Diluted earnings per share attributable to Cubic (in dollars per share)	$ 0.15	$ (0.04)	$ (0.28)	$ (0.04)