Acquisitions and Divestitures - CGD Services - Income (loss) from discontinued operations (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Jun. 30, 2018	Apr. 18, 2018
Costs and expenses:
Net income from discontinued operations	$ (1,339)	$ 1,335	$ (1,339)	$ 2,984
Cubic Global Defense Services | Disposed of by sale
Divestitures
Consideration from sale						$ 133,800	$ 135,000
Working capital settlement receivable	1,300		1,300		$ 3,700
Receivable for estimated earn-out amount due from purchaser	3,000		3,000		$ 3,000
Receivable for estimated amount due from purchaser	0		0
Income (loss) from discontinued operations
Net sales		98,068		190,361
Costs and expenses:
Cost of sales		87,562		170,682
Selling, general and administrative expenses		3,876		7,543
Amortization of purchased intangibles		489		1,097
Restructuring costs		7		7
Other income		(8)		(13)
Earnings from discontinued operations before income taxes		6,142		11,045
Net loss on sale	1,339	6,900	1,339	6,900
Income tax provision (benefit)		(2,093)		1,161
Net income from discontinued operations	$ (1,339)	$ 1,335	$ (1,339)	$ 2,984