Document and Entity Information - USD ($)	12 Months Ended
	Sep. 30, 2020	Jan. 26, 2021	Mar. 31, 2020
Document Information [Line Items]
Document Type	10-K/A
Document Annual Report	true
Document Transition Report	false
Document Period End Date	Sep. 30, 2020
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
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
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		31,834,085
Entity Public Float			$ 788,872,127
Current Fiscal Year End Date	--09-30
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Entity Central Index Key	0000026076
Amendment Flag	true
Amendment Description	This Amendment No. 1 on Form 10-K/A (this “Amendment”) amends our Annual Report on Form 10-K for the fiscal year ended September 30, 2020, originally filed with the Securities and Exchange Commission (the “SEC”) on November 18, 2020 (the “Original Filing”). We are filing this Amendment to include the information required by Part III of Form 10-K and not included in the Original Filing, as we did not file a definitive proxy statement for an annual meeting of shareholders within 120 days of the end of our fiscal year ended September 30, 2020. In addition, in connection with the filing of this Amendment and pursuant to the rules of the SEC, we are including new certifications of our principal executive officer and principal financial officer pursuant to Section 302 of the Sarbanes-Oxley Act of 2002. Accordingly, Item 15 of Part IV of Form 10-K has also been amended to reflect the filings of these new certifications.Except as described above, no other changes have been made to the Original Filing. The Original Filing continues to speak as of the date of the Original Filing, and we have not updated the disclosures contained therein to reflect any events which occurred at a date subsequent to the filing of the Original Filing. Accordingly, this Amendment should be read in conjunction with the Original Filing and with our filings with the SEC subsequent to the filing of the Original Filing.Except as the context otherwise requires, the terms “we,” “us,” the “Company,” “Cubic” and “Registrant” as used herein are references to Cubic Corporation, a Delaware corporation, and its consolidated subsidiaries. Terms used but not defined herein are defined in the Original Filing.
Common Stock
Document Information [Line Items]
Title of 12(b) Security	Common Stock, no par value
Trading Symbol	CUB
Security Exchange Name	NYSE
Preferred Stock Purchase Rights
Document Information [Line Items]
Title of 12(b) Security	Preferred Stock Purchase Rights
No Trading Symbol Flag	false
Security Exchange Name	NYSE