Segment Information - Business segment financial data (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Segment Information
Total sales	$ 305,259	$ 248,391
Operating income (loss)	(566)	(11,902)
Depreciation and amortization	16,011	12,433
Transportation Systems
Segment Information
Total sales	181,807	146,500
Operating income (loss)	10,976	9,900
Depreciation and amortization	7,700	3,300
Cubic Mission Solutions
Segment Information
Total sales	46,393	33,100
Operating income (loss)	(4,940)	(8,900)
Depreciation and amortization	5,400	5,900
Cubic Global Defense
Segment Information
Total sales	77,059	68,800
Operating income (loss)	2,897	1,400
Depreciation and amortization	2,200	2,100
Corporate
Segment Information
Depreciation and amortization	700	1,100
Unallocated corporate expenses and other
Segment Information
Operating income (loss)	$ (9,499)	$ (14,300)