Acquisitions - Goodwill and Pro forma information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Changes in the carrying amount of goodwill
Balance at the beginning of the period			$ 237,899
Acquisitions			173,600
Foreign currency exchange rate changes			(5,300)
Balance at the end of the period	$ 406,249		406,249
Unaudited pro forma information
Net sales	375,200	$ 367,000	1,075,100	$ 1,061,700
Net income attributable to Cubic	4,500	8,800	8,300	2,500
Adjustments made for transaction expenses	0	$ 0	0	$ 0
Cubic Transportation Systems
Changes in the carrying amount of goodwill
Balance at the beginning of the period			56,000
Foreign currency exchange rate changes			(5,400)
Balance at the end of the period	50,600		50,600
Cubic Global Defense Systems
Changes in the carrying amount of goodwill
Balance at the beginning of the period			87,500
Acquisitions			173,600
Foreign currency exchange rate changes			100
Balance at the end of the period	261,200		261,200
Cubic Global Defense Services
Changes in the carrying amount of goodwill
Balance at the beginning of the period			94,400
Balance at the end of the period	$ 94,400		$ 94,400