Segment Information - Schedule of Segment Revenues, Depreciation and Amortization, and Operating (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 25, 2016	Sep. 27, 2015	Sep. 25, 2016	Sep. 27, 2015
Revenues:
Service revenues	$ 87.2	$ 87.4	$ 258.0	$ 263.5
Product sales	78.2	74.3	228.6	216.1
Total revenues	165.4	161.7	486.6	479.6
Depreciation & amortization:
Total depreciation and amortization			17.3	19.5
Operating income (loss) from continuing operations:
Total operating income (loss) from continuing operations	(13.0)	1.6	(23.2)	(6.0)
Reportable Segments
Depreciation & amortization:
Total depreciation and amortization	5.6	5.9	17.3	19.5
Reportable Segments | Kratos Government Solutions
Revenues:
Service revenues	52.9	54.3	163.1	157.4
Product sales	59.9	54.4	178.3	165.8
Total revenues	112.8	108.7	341.4	323.2
Depreciation & amortization:
Total depreciation and amortization	3.6	4.2	11.3	14.3
Operating income (loss) from continuing operations:
Total operating income (loss) from continuing operations	7.7	3.7	10.4	6.3
Reportable Segments | Public Safety & Security
Revenues:
Service revenues	34.3	33.1	94.9	106.1
Product sales	0.0	0.0	0.0	0.0
Total revenues	34.3	33.1	94.9	106.1
Depreciation & amortization:
Total depreciation and amortization	0.1	0.1	0.4	0.4
Operating income (loss) from continuing operations:
Total operating income (loss) from continuing operations	0.8	0.4	(1.7)	1.0
Reportable Segments | Unmanned Systems
Revenues:
Service revenues	0.0	0.0	0.0	0.0
Product sales	18.3	19.9	50.3	50.3
Total revenues	18.3	19.9	50.3	50.3
Depreciation & amortization:
Total depreciation and amortization	1.9	1.6	5.6	4.8
Operating income (loss) from continuing operations:
Total operating income (loss) from continuing operations	(20.4)	(0.6)	(27.6)	(7.3)
Unallocated corporate expense, net
Operating income (loss) from continuing operations:
Total operating income (loss) from continuing operations	$ (1.1)	$ (1.9)	$ (4.3)	$ (6.0)