Acquisitions and Divestitures - CGD Services - Income (loss) from discontinued operations (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		4 Months Ended	9 Months Ended
	Mar. 31, 2018	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2018	Jun. 30, 2017	Apr. 18, 2018
Costs and expenses:
Income tax provision (benefit)					$ 500
Net income from discontinued operations		$ 5,380	$ 56,279		8,364	$ 10,985
Cubic Global Defense Services | Discontinued operations held-for-sale
Divestitures
Sales price in the definitive agreement							$ 135,000
Additional cash payment to be received based on achievement of pre-determined earn-out conditions		3,000		$ 3,000	3,000
Consideration received in connection with sale		133,800
Receivable for estimated amount due from purchaser		3,700		3,700	3,700
Net (gain) loss on sale	$ (6,900)	819		(6,100)	(6,081)
Estimated selling costs	4,200
Income (loss) from discontinued operations
Net sales		71,867	95,685		262,228	281,661
Costs and expenses:
Cost of sales		64,597	86,706		235,279	255,995
Selling, general and administrative expenses		3,133	3,196		10,676	12,478
Amortization of purchased intangibles		276	608		1,373	2,145
Restructuring costs					7	334
Other income		(2)	(9)		(15)	(42)
Earnings from discontinued operations before income taxes		3,863	5,184		14,908	10,751
Net (gain) loss on sale	$ 6,900	(819)		$ 6,100	6,081
Income tax provision (benefit)		(698)	(51,095)		463	(234)
Net income from discontinued operations		$ 5,380	$ 56,279		$ 8,364	$ 10,985