Document and Entity Information - USD ($)	12 Months Ended
	Sep. 30, 2019	Nov. 01, 2019	Mar. 31, 2019
Document and Entity Information
Document Type	10-K
Document Annual Report	true
Document Transition Report	false
Document Period End Date	Sep. 30, 2019
Entity File Number	001-08931
Entity Registrant Name	CUBIC CORP /DE/
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	95-1678055
Entity Address, Address Line One	9333 Balboa Avenue
Entity Address, City or Town	San Diego
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	92123
City Area Code	858
Local Phone Number	277-6780
Title of 12(b) Security	Common Stock
Trading Symbol	CUB
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		31,274,052
Entity Public Float			$ 1,274,404,537
Current Fiscal Year End Date	--09-30
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Entity Central Index Key	0000026076
Amendment Flag	false