Segment Information - Schedule of Segment Revenues, Depreciation and Amortization, and Operating (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jul. 01, 2018	Jun. 25, 2017	Jul. 01, 2018	Jun. 25, 2017
Revenues:
Total revenues	$ 151.2	$ 147.9	$ 294.2	$ 279.9
Depreciation & amortization:
Total depreciation and amortization			9.2	10.9
Operating income from continuing operations:
Operating income from continuing operations	2.6	1.5	9.6	2.9
Service
Revenues:
Total revenues	47.0	53.8	93.0	103.0
Product
Revenues:
Total revenues	104.2	94.1	201.2	176.9
Kratos Government Solutions
Revenues:
Total revenues	115.6		230.8
Unmanned Systems
Revenues:
Total revenues	35.6		63.4
Reportable Segments
Depreciation & amortization:
Total depreciation and amortization	4.7	5.4	9.2	10.9
Reportable Segments | Kratos Government Solutions
Revenues:
Total revenues	115.6	125.7	230.8	242.1
Depreciation & amortization:
Total depreciation and amortization	3.3	3.6	6.9	7.3
Operating income from continuing operations:
Operating income from continuing operations	5.0	5.2	12.9	14.3
Reportable Segments | Kratos Government Solutions | Service
Revenues:
Total revenues	47.0	53.8	93.0	103.0
Reportable Segments | Kratos Government Solutions | Product
Revenues:
Total revenues	68.6	71.9	137.8	139.1
Reportable Segments | Unmanned Systems
Revenues:
Total revenues	35.6	22.2	63.4	37.8
Depreciation & amortization:
Total depreciation and amortization	1.4	1.8	2.3	3.6
Operating income from continuing operations:
Operating income from continuing operations	2.0	(1.9)	2.8	(6.9)
Reportable Segments | Unmanned Systems | Service
Revenues:
Total revenues	0.0	0.0	0.0	0.0
Reportable Segments | Unmanned Systems | Product
Revenues:
Total revenues	35.6	22.2	63.4	37.8
Unallocated corporate expense, net
Operating income from continuing operations:
Operating income from continuing operations	$ (4.4)	$ (1.8)	$ (6.1)	$ (4.5)