New Accounting Standards Implemented - Effect on Statement of Operations (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Sep. 30, 2018
Net sales:
Net sales	$ 305,259	$ 248,391
Costs and expenses:
Selling, general and administrative expenses	62,986	61,680
Research and development	12,012	11,977
Amortization of purchased intangibles	10,565	7,351
Restructuring costs	1,992	1,495
Total costs and expenses	305,825	260,293
Operating loss	(566)	(11,902)
Other income (expenses):
Interest and dividend income	1,234	482
Interest expense	(4,032)	(2,674)
Other income (expense), net	(4,753)	(78)
Loss from continuing operations before income taxes	(8,117)	(14,172)
Income tax (benefit) provision	2,497	(2,737)
Net loss	(10,614)	(9,786)
Less noncontrolling interest in loss of VIE	(4,027)
Net loss attributable to Cubic	$ (6,587)	$ (9,786)
Basic
Basic earnings per share attributable to Cubic (in dollars per share)	$ (0.23)	$ (0.36)
Diluted
Diluted earnings per share attributable to Cubic (in dollars per share)	$ (0.23)	$ (0.36)
ASC 605 | ASU 2014-09
Net sales:
Net sales	$ 276,824
Costs and expenses:
Selling, general and administrative expenses	62,823
Research and development	12,012
Amortization of purchased intangibles	10,565
Restructuring costs	1,992
Total costs and expenses	280,721
Operating loss	(3,897)
Other income (expenses):
Interest and dividend income	56
Interest expense	(4,032)
Other income (expense), net	(4,753)
Loss from continuing operations before income taxes	(12,626)
Income tax (benefit) provision	2,473
Net loss	(15,099)
Less noncontrolling interest in loss of VIE	(5,981)
Net loss attributable to Cubic	$ (9,118)
Basic
Basic earnings per share attributable to Cubic (in dollars per share)	$ (0.32)
Diluted
Diluted earnings per share attributable to Cubic (in dollars per share)	$ (0.32)
ASC 606 | ASU 2014-09
Net sales:
Net sales	$ 28,435		$ 114,900
Costs and expenses:
Selling, general and administrative expenses	163
Total costs and expenses	25,104
Operating loss	3,331
Other income (expenses):
Interest and dividend income	1,178
Loss from continuing operations before income taxes	4,509
Income tax (benefit) provision	24
Net loss	4,485
Less noncontrolling interest in loss of VIE	1,954
Net loss attributable to Cubic	$ 2,531
Basic
Basic earnings per share attributable to Cubic (in dollars per share)	$ 0.09
Diluted
Diluted earnings per share attributable to Cubic (in dollars per share)	$ 0.09
Products
Net sales:
Net sales	$ 182,253	$ 131,743
Costs and expenses:
Costs	125,485	91,573
Products | ASC 605 | ASU 2014-09
Net sales:
Net sales	152,562
Costs and expenses:
Costs	100,544
Products | ASC 606 | ASU 2014-09
Net sales:
Net sales	29,691
Costs and expenses:
Costs	24,941
Services
Net sales:
Net sales	123,006	116,648
Costs and expenses:
Costs	92,785	$ 86,217
Services | ASC 605 | ASU 2014-09
Net sales:
Net sales	124,262
Costs and expenses:
Costs	92,785
Services | ASC 606 | ASU 2014-09
Net sales:
Net sales	$ (1,256)