Segment Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 27, 2015	Sep. 28, 2014	Sep. 27, 2015	Sep. 28, 2014	Dec. 28, 2014
Revenues:
Service revenues	$ 87.4	$ 97.1	$ 263.5	$ 299.5
Product sales	74.3	93.7	216.1	271.4
Total revenues	161.7	190.8	479.6	570.9
Depreciation & amortization:
Total depreciation and amortization			19.5	24.2
Operating income (loss) from continuing operations:
Total operating income (loss) from continuing operations	1.6	(3.0)	(6.0)	(0.3)
Total assets	921.5		921.5		$ 1,138.8
Discontinued operations, Assets	0.0		0.0		190.8
Reportable Segments
Revenues:
Total revenues	161.7	190.8	479.6	570.9
Depreciation & amortization:
Total depreciation and amortization	5.9	8.4	19.5	24.2
Unallocated corporate expense, net
Operating income (loss) from continuing operations:
Total operating income (loss) from continuing operations	(1.9)	(2.9)	(6.0)	(8.3)
Total assets	65.2		65.2		62.8
Kratos Government Solutions | Reportable Segments
Revenues:
Service revenues	54.3	54.3	157.4	157.2
Product sales	54.4	70.8	165.8	198.0
Total revenues	108.7	125.1	323.2	355.2
Depreciation & amortization:
Total depreciation and amortization	4.2	5.9	14.3	17.6
Operating income (loss) from continuing operations:
Total operating income (loss) from continuing operations	3.7	7.4	6.3	15.4
Total assets	595.9		595.9		618.9
Public Safety & Security | Reportable Segments
Revenues:
Service revenues	33.1	42.8	106.1	142.3
Product sales	0.0	0.0	0.0	13.0
Total revenues	33.1	42.8	106.1	155.3
Depreciation & amortization:
Total depreciation and amortization	0.1	0.5	0.4	1.5
Operating income (loss) from continuing operations:
Total operating income (loss) from continuing operations	0.4	(4.2)	1.0	(0.5)
Total assets	94.4		94.4		100.2
Unmanned Systems | Reportable Segments
Revenues:
Service revenues	0.0	0.0	0.0	0.0
Product sales	19.9	22.9	50.3	60.4
Total revenues	19.9	22.9	50.3	60.4
Depreciation & amortization:
Total depreciation and amortization	1.6	2.0	4.8	5.1
Operating income (loss) from continuing operations:
Total operating income (loss) from continuing operations	(0.6)	$ (3.3)	(7.3)	$ (6.9)
Total assets	$ 166.0		$ 166.0		$ 166.1