Segment Information - Schedule of Segment Revenues, Depreciation and Amortization, and Operating (Loss) (Details) - USD ($) $ in Millions	3 Months Ended
	Apr. 01, 2018	Mar. 26, 2017
Revenues:
Service revenues	$ 46.0	$ 49.2
Product sales	97.0	82.8
Total revenues	143.0	132.0
Depreciation & amortization:
Total depreciation and amortization	4.5	5.5
Operating income (loss) from continuing operations:
Total operating income from continuing operations	7.0	1.4
Reportable Segments
Depreciation & amortization:
Total depreciation and amortization	4.5	5.5
Operating income (loss) from continuing operations:
Total operating income from continuing operations	8.7	4.1
Reportable Segments | Kratos Government Solutions
Revenues:
Service revenues	46.0	49.2
Product sales	69.2	67.2
Total revenues	115.2	116.4
Depreciation & amortization:
Total depreciation and amortization	3.6	3.7
Operating income (loss) from continuing operations:
Total operating income from continuing operations	7.9	9.1
Reportable Segments | Unmanned Systems
Revenues:
Service revenues	0.0	0.0
Product sales	27.8	15.6
Total revenues	27.8	15.6
Depreciation & amortization:
Total depreciation and amortization	0.9	1.8
Operating income (loss) from continuing operations:
Total operating income from continuing operations	0.8	(5.0)
Unallocated corporate expense, net
Operating income (loss) from continuing operations:
Total operating income from continuing operations	$ (1.7)	$ (2.7)