Implementation of the New Revenue Recognition Standard - Effect on Statement of Operations (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Net sales:
Net sales	$ 382,679	$ 296,212	$ 1,025,277	$ 823,189
Costs and expenses:
Selling, general and administrative expenses	82,167	58,267	211,348	183,720
Research and development	12,470	13,934	38,236	40,113
Amortization of purchased intangibles	9,717	6,153	32,677	19,988
Gain on sale of fixed assets	(32,563)		(32,563)
Restructuring costs	8,505	1,631	12,254	3,382
Total costs and expenses	347,954	285,922	997,659	826,480
Operating income (loss)	34,725	10,290	27,618	(3,291)
Other income (expenses):
Interest and dividend income	1,696	765	4,343	1,872
Interest expense	(6,132)	(2,567)	(14,695)	(8,152)
Other income (expense), net	(8,714)	(3,831)	(17,069)	(1,881)
Income (loss) from continuing operations before income taxes	21,575	4,657	197	(11,452)
Income tax (benefit) provision	1,029	5,627	(305)	4,299
Income (loss) from continuing operations	20,546	(970)	502	(15,751)
Net loss from discontinued operations	(202)	5,380	(1,541)	8,364
Net income (loss)	20,344	4,410	(1,039)	(7,387)
Less noncontrolling interest in loss of VIE	(3,566)	(1,881)	(8,970)	(1,881)
Net income (loss) attributable to Cubic	23,910	6,291	7,931	(5,506)
Amounts attributable to Cubic:
Net income from continuing operations	24,112	911	9,472	(13,870)
Net loss from discontinued operations	(202)	5,380	(1,541)	8,364
Net income (loss) attributable to Cubic	$ 23,910	$ 6,291	$ 7,931	$ (5,506)
Basic
Basic earnings per share attributable to Cubic (in dollars per share)	$ 0.77	$ 0.23	$ 0.26	$ (0.20)
Diluted
Diluted earnings per share attributable to Cubic (in dollars per share)	$ 0.77	$ 0.23	$ 0.26	$ (0.20)
ASC 605 | ASU 2014-09
Net sales:
Net sales	$ 367,394		$ 953,853
Costs and expenses:
Selling, general and administrative expenses	81,673		210,791
Research and development	12,470		38,236
Amortization of purchased intangibles	9,717		32,677
Gain on sale of fixed assets	(32,563)		(32,563)
Restructuring costs	8,505		12,254
Total costs and expenses	336,307		938,597
Operating income (loss)	31,087		15,256
Other income (expenses):
Interest and dividend income	39		169
Interest expense	(6,132)		(14,695)
Other income (expense), net	(8,714)		(17,069)
Income (loss) from continuing operations before income taxes	16,280		(16,339)
Income tax (benefit) provision	1,113		(467)
Income (loss) from continuing operations	15,167		(15,872)
Net loss from discontinued operations	(202)		(1,541)
Net income (loss)	14,965		(17,413)
Less noncontrolling interest in loss of VIE	(7,074)		(16,940)
Net income (loss) attributable to Cubic	22,039		(473)
Amounts attributable to Cubic:
Net income from continuing operations	22,241		1,068
Net loss from discontinued operations	(202)		(1,541)
Net income (loss) attributable to Cubic	$ 22,039		$ (473)
Basic
Basic earnings per share attributable to Cubic (in dollars per share)	$ 0.71		$ (0.02)
Diluted
Diluted earnings per share attributable to Cubic (in dollars per share)	$ 0.71		$ (0.02)
ASC 606 | ASU 2014-09
Net sales:
Net sales	$ 15,285		$ 71,424
Costs and expenses:
Selling, general and administrative expenses	494		557
Total costs and expenses	11,647		59,062
Operating income (loss)	3,638		12,362
Other income (expenses):
Interest and dividend income	1,657		4,174
Income (loss) from continuing operations before income taxes	5,295		16,536
Income tax (benefit) provision	(84)		162
Income (loss) from continuing operations	5,379		16,374
Net income (loss)	5,379		16,374
Less noncontrolling interest in loss of VIE	3,508		7,970
Net income (loss) attributable to Cubic	1,871		8,404
Amounts attributable to Cubic:
Net income from continuing operations	1,871		8,404
Net income (loss) attributable to Cubic	$ 1,871		$ 8,404
Basic
Basic earnings per share attributable to Cubic (in dollars per share)	$ 0.06		$ 0.28
Diluted
Diluted earnings per share attributable to Cubic (in dollars per share)	$ 0.06		$ 0.28
Products
Net sales:
Net sales	$ 255,900	$ 179,761	$ 660,897	$ 468,949
Costs and expenses:
Costs	190,434	125,536	491,856	334,202
Products | ASC 605 | ASU 2014-09
Net sales:
Net sales	240,604		588,754
Costs and expenses:
Costs	179,281		433,351
Products | ASC 606 | ASU 2014-09
Net sales:
Net sales	15,296		72,143
Costs and expenses:
Costs	11,153		58,505
Services
Net sales:
Net sales	126,779	116,451	364,380	354,240
Costs and expenses:
Costs	77,224	$ 80,401	243,851	$ 245,075
Services | ASC 605 | ASU 2014-09
Net sales:
Net sales	126,790		365,099
Costs and expenses:
Costs	77,224		243,851
Services | ASC 606 | ASU 2014-09
Net sales:
Net sales	$ (11)		$ (719)