Segment Information - Schedule of Segment Revenues, Depreciation and Amortization, and Operating (Loss) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Apr. 01, 2018
Segment Reporting Information [Line Items]
Total revenues	$ 160.4	$ 143.0
Depreciation & amortization:
Total depreciation and amortization	5.1	4.5
Operating income from continuing operations:
Total operating income from continuing operations	8.2	7.0
Kratos Government Solutions
Segment Reporting Information [Line Items]
Total revenues	125.5	115.2
Unmanned Systems
Segment Reporting Information [Line Items]
Total revenues	34.9	27.8
Reportable Segments
Depreciation & amortization:
Total depreciation and amortization	5.1	4.5
Operating income from continuing operations:
Total operating income from continuing operations	12.0	8.7
Reportable Segments | Kratos Government Solutions
Segment Reporting Information [Line Items]
Total revenues	125.5	115.2
Depreciation & amortization:
Total depreciation and amortization	3.9	3.6
Operating income from continuing operations:
Total operating income from continuing operations	11.4	7.9
Reportable Segments | Unmanned Systems
Segment Reporting Information [Line Items]
Total revenues	34.9	27.8
Depreciation & amortization:
Total depreciation and amortization	1.2	0.9
Operating income from continuing operations:
Total operating income from continuing operations	0.6	0.8
Unallocated corporate expense, net
Operating income from continuing operations:
Total operating income from continuing operations	(3.8)	(1.7)
Service revenues
Segment Reporting Information [Line Items]
Total revenues	62.6	46.0
Service revenues | Reportable Segments | Kratos Government Solutions
Segment Reporting Information [Line Items]
Total revenues	62.6	46.0
Service revenues | Reportable Segments | Unmanned Systems
Segment Reporting Information [Line Items]
Total revenues	0.0	0.0
Product sales
Segment Reporting Information [Line Items]
Total revenues	97.8	97.0
Product sales | Reportable Segments | Kratos Government Solutions
Segment Reporting Information [Line Items]
Total revenues	62.9	69.2
Product sales | Reportable Segments | Unmanned Systems
Segment Reporting Information [Line Items]
Total revenues	$ 34.9	$ 27.8