Acquisitions and Divestitures - CGD Services - Assets and liabilities of discontinued (Details) - Discontinued operations held-for-sale - Cubic Global Defense Services - USD ($) $ in Thousands	9 Months Ended
	Jun. 30, 2018	Sep. 30, 2017
Assets and liabilities
Accounts receivable, net		$ 74,710
Other current assets		1,190
Property and equipment, net		466
Goodwill		94,350
Purchased intangibles, net		8,637
Other noncurrent assets		(5,179)
Total assets		174,174
Accounts payable and other liabilities		36,862
Net assets		$ 137,312
Period for post closing support services from close date	7 years