BUSINESS SEGMENT INFORMATION - Financial data (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Sep. 30, 2016 USD ($) segment	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)
Revenue recognition
Number of primary business segments | segment									3
Sales	$ 406,588	$ 375,240	$ 366,024	$ 313,813	$ 425,917	$ 347,806	$ 338,834	$ 318,488	$ 1,461,665	$ 1,431,045	$ 1,398,352
Operating income (loss)	10,488	$ 13,893	$ (9,086)	$ (8,077)	34,709	$ 10,293	$ 23,206	$ 7,179	7,218	75,387	92,490
Assets	1,504,679				1,300,276				1,504,679	1,300,276	1,194,600
Depreciation and amortization									45,478	37,662	30,440
Capital expenditures									32,093	22,202	16,620
Cubic Transportation Systems
Revenue recognition
Sales									586,400	566,800	599,700
Operating income (loss)									57,500	75,900	65,900
Assets	338,200				410,000				338,200	410,000	422,200
Depreciation and amortization									8,200	10,800	11,500
Capital expenditures									2,200	2,000	1,800
Cubic Global Defense Systems
Revenue recognition
Sales									484,200	462,100	400,600
Operating income (loss)									(17,100)	18,400	26,800
Assets	616,200				341,200				616,200	341,200	252,400
Depreciation and amortization									28,700	17,100	7,400
Capital expenditures									8,900	600	13,200
Cubic Global Defense Services
Revenue recognition
Sales									391,100	402,100	398,100
Operating income (loss)									11,200	6,600	7,800
Assets	191,200				200,700				191,200	200,700	195,800
Depreciation and amortization									5,200	8,500	10,700
Corporate
Revenue recognition
Assets	$ 359,100				$ 348,400				359,100	348,400	324,200
Depreciation and amortization									3,400	1,300	800
Capital expenditures									21,000	19,600	1,600
Unallocated corporate expenses and other
Revenue recognition
Operating income (loss)									$ (44,400)	$ (25,500)	$ (8,000)