SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - EPS (Details) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2016 USD ($) $ / shares	Jun. 30, 2016 USD ($) $ / shares	Mar. 31, 2016 USD ($) $ / shares	Dec. 31, 2015 USD ($) $ / shares	Sep. 30, 2015 USD ($) $ / shares	Jun. 30, 2015 USD ($) $ / shares	Mar. 31, 2015 USD ($) $ / shares	Dec. 31, 2014 USD ($) $ / shares	Sep. 30, 2016 USD ($) item $ / shares shares	Sep. 30, 2015 USD ($) contract $ / shares shares	Sep. 30, 2014 USD ($) $ / shares shares
Revenue Recognition
Number of estimates, a change in which could have material effect on financial position or results of operations | item									1
Allocation of arrangement consideration to the up-front deliverables | $									$ 0
Revenue for the delivery of up-front units of accounting | $									$ 0
Number of transportation systems service contracts, which contain annual system usage incentives | contract										1
Stock-Based Compensation
Vesting period of performance-based RSUs									3 years
Net Income Per Share
Net income (loss) attributable to Cubic | $	$ (7,493)	$ 4,498	$ 10,144	$ (5,414)	$ 19,977	$ 8,780	$ (11,024)	$ 5,152	$ 1,735	$ 22,885	$ 69,491
Weighted average shares - basic | shares									26,976	26,872	26,787
Effect of dilutive securities (in shares) | shares									64	66	58
Weighted average shares - diluted | shares									27,040	26,938	26,845
Basic (in dollars per share) | $ / shares	$ (0.29)	$ 0.17	$ 0.38	$ (0.20)	$ 0.74	$ 0.33	$ (0.41)	$ 0.19	$ 0.06	$ 0.85	$ 2.59
Diluted (in dollars per share) | $ / shares	$ (0.29)	$ 0.17	$ 0.38	$ (0.20)	$ 0.74	$ 0.33	$ (0.41)	$ 0.19	$ 0.06	$ 0.85	$ 2.59