Acquisitions - Goodwill and Pro forma information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2016	Mar. 31, 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			(2,100)
Balance at the end of the period	$ 409,442		409,442
Unaudited pro forma information
Net sales	367,300	$ 352,100	699,900	$ 694,700
Net income attributable to Cubic	9,500	(12,400)	3,800	(6,300)
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			(2,300)
Balance at the end of the period	53,700		53,700
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			200
Balance at the end of the period	261,300		261,300
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