Segment Information - Schedule of Segment Revenues, Depreciation and Amortization, and Operating (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Oct. 01, 2017	Sep. 30, 2018	Oct. 01, 2017
Revenues:
Total revenues	$ 159.4	$ 157.1	$ 453.6	$ 437.0
Depreciation & amortization:
Total depreciation and amortization			13.6	16.8
Operating income from continuing operations:
Operating income from continuing operations	10.1	0.1	19.7	3.0
Service
Revenues:
Total revenues	54.9	47.6	147.9	150.6
Product
Revenues:
Total revenues	104.5	109.5	305.7	286.4
Kratos Government Solutions
Revenues:
Total revenues	126.1		356.9
Unmanned Systems
Revenues:
Total revenues	33.3		96.7
Reportable Segments
Depreciation & amortization:
Total depreciation and amortization	4.4	5.9	13.6	16.8
Reportable Segments | Kratos Government Solutions
Revenues:
Total revenues	126.1	115.5	356.9	357.6
Depreciation & amortization:
Total depreciation and amortization	3.3	3.5	10.2	10.8
Operating income from continuing operations:
Operating income from continuing operations	11.0	1.4	23.9	15.7
Reportable Segments | Kratos Government Solutions | Service
Revenues:
Total revenues	54.9	47.6	147.9	150.6
Reportable Segments | Kratos Government Solutions | Product
Revenues:
Total revenues	71.2	67.9	209.0	207.0
Reportable Segments | Unmanned Systems
Depreciation & amortization:
Total depreciation and amortization	1.1	2.4	3.4	6.0
Operating income from continuing operations:
Operating income from continuing operations	1.0	1.5	3.8	(5.4)
Reportable Segments | Unmanned Systems | Product
Revenues:
Total revenues	33.3	41.6	96.7	79.4
Unallocated corporate expense, net
Operating income from continuing operations:
Operating income from continuing operations	$ (1.9)	$ (2.8)	$ (8.0)	$ (7.3)