Segment Information - Schedule of Segment Revenues, Depreciation and Amortization, and Operating (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 28, 2020	Jun. 30, 2019	Jun. 28, 2020	Jun. 30, 2019
Segment Reporting Information [Line Items]
Total revenues	$ 170.4	$ 187.9	$ 339.3	$ 348.3
Depreciation & amortization:
Total depreciation and amortization	6.0	6.0	12.3	11.1
Operating income from continuing operations:
Total operating income from continuing operations	2.9	9.0	7.6	17.2
Service revenues
Segment Reporting Information [Line Items]
Total revenues	62.9	73.7	126.5	136.3
Product sales
Segment Reporting Information [Line Items]
Total revenues	107.5	114.2	212.8	212.0
Kratos Government Solutions
Segment Reporting Information [Line Items]
Total revenues	128.4	145.4	255.3	270.9
Depreciation & amortization:
Total depreciation and amortization	4.4	4.8	9.1	8.7
Kratos Government Solutions | Service revenues
Segment Reporting Information [Line Items]
Total revenues	62.9	73.7	126.5	136.3
Kratos Government Solutions | Product sales
Segment Reporting Information [Line Items]
Total revenues	65.5	71.7	128.8	134.6
Unmanned Systems
Segment Reporting Information [Line Items]
Total revenues	42.0	42.5	84.0	77.4
Depreciation & amortization:
Total depreciation and amortization	1.6	1.2	3.2	2.4
Reportable Segments | Kratos Government Solutions
Operating income from continuing operations:
Total operating income from continuing operations	7.7	10.7	17.0	22.1
Reportable Segments | Unmanned Systems
Operating income from continuing operations:
Total operating income from continuing operations	1.0	1.7	1.5	2.3
Corporate activities
Operating income from continuing operations:
Total operating income from continuing operations	$ (5.8)	$ (3.4)	$ (10.9)	$ (7.2)