Segment Information - Schedule of Segment Revenues, Depreciation and Amortization, and Operating (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 25, 2017	Jun. 26, 2016	Jun. 25, 2017	Jun. 26, 2016
Revenues:
Service revenues	$ 91.6	$ 88.2	$ 176.6	$ 170.8
Product sales	94.1	80.0	176.9	150.4
Total revenues	185.7	168.2	353.5	321.2
Depreciation & amortization:
Total depreciation and amortization			11.0	11.7
Operating income (loss) from continuing operations:
Total operating income (loss) from continuing operations	2.6	0.0	4.3	(10.2)
Reportable Segments
Depreciation & amortization:
Total depreciation and amortization	5.4	5.6	11.0	11.7
Reportable Segments | Kratos Government Solutions
Revenues:
Service revenues	53.7	57.8	101.9	110.2
Product sales	71.9	62.2	139.1	118.4
Total revenues	125.6	120.0	241.0	228.6
Depreciation & amortization:
Total depreciation and amortization	3.5	3.6	7.2	7.7
Operating income (loss) from continuing operations:
Total operating income (loss) from continuing operations	5.7	4.5	15.3	2.7
Reportable Segments | Public Safety & Security
Revenues:
Service revenues	37.9	30.4	74.7	60.6
Product sales	0.0	0.0	0.0	0.0
Total revenues	37.9	30.4	74.7	60.6
Depreciation & amortization:
Total depreciation and amortization	0.1	0.2	0.2	0.3
Operating income (loss) from continuing operations:
Total operating income (loss) from continuing operations	0.5	0.2	0.3	(2.5)
Reportable Segments | Unmanned Systems
Revenues:
Service revenues	0.0	0.0	0.0	0.0
Product sales	22.2	17.8	37.8	32.0
Total revenues	22.2	17.8	37.8	32.0
Depreciation & amortization:
Total depreciation and amortization	1.8	1.8	3.6	3.7
Operating income (loss) from continuing operations:
Total operating income (loss) from continuing operations	(1.8)	(3.0)	(6.8)	(7.2)
Unallocated corporate expense, net
Operating income (loss) from continuing operations:
Total operating income (loss) from continuing operations	$ (1.8)	$ (1.7)	$ (4.5)	$ (3.2)