Variable Interest Entities - Net assets and liabilities (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Sep. 30, 2019
ASSETS
Total assets	$ 1,920,029		$ 1,847,170
LIABILITIES AND SHAREHOLDERS' EQUITY
Shareholders' equity related to Cubic	951,619		961,649
Noncontrolling interest in VIE	22,909		18,919
Total liabilities and shareholders' equity	1,920,029		1,847,170
Revenue	328,839	$ 305,259
Operating income (loss)	(6,483)	(566)
Other income (expense), net	(127)	(4,753)
VIE
ASSETS
Cash	410		347
Restricted cash	9,967		9,967
Other current assets	79		33
Long-term contracts financing receivables	124,576		115,508
Other noncurrent assets			1,419
Total assets	135,032		127,274
LIABILITIES AND SHAREHOLDERS' EQUITY
Trade accounts payable			25
Accrued compensation and other current liabilities	171		191
Due to Cubic	11,861		25,143
Other noncurrent liabilities	17,267		21,605
Long-term debt	82,984		61,994
Total liabilities	112,283		108,958
Shareholders' equity related to Cubic	(160)		(603)
Noncontrolling interest in VIE	22,909		18,919
Total liabilities and shareholders' equity	135,032		$ 127,274
Revenue	1,245	1,961
Operating income (loss)	972	1,668
Other income (expense), net	3,071	(6,133)
Interest income	1,553	503
Interest Expense	$ (1,159)	$ (512)