Acquisitions and Divestitures - CGD Services - Income (loss) from discontinued operations (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Jun. 30, 2018	Apr. 18, 2018
Costs and expenses:
Net income from discontinued operations		$ 1,649
Cubic Global Defense Services
Divestitures
Receivable for estimated amount due from purchaser	$ 0
Cubic Global Defense Services | Disposed of by sale
Divestitures
Consideration from sale			$ 133,800	$ 135,000
Working capital settlement receivable	3,700
Receivable for estimated earn-out amount due from purchaser	3,000
Income (loss) from discontinued operations
Net sales		92,293
Costs and expenses:
Cost of sales		83,120
Selling, general and administrative expenses		3,667
Amortization of purchased intangibles		608
Other income		(5)
Earnings from discontinued operations before income taxes		4,903
Income tax provision (benefit)		3,254
Net income from discontinued operations	$ 0	$ 1,649