Segment Information (Details) (USD $) In Millions, unless otherwise specified	0 Months Ended	3 Months Ended								12 Months Ended
	Jul. 02, 2013	Dec. 29, 2013	Sep. 29, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 30, 2012	Sep. 30, 2012	Jun. 24, 2012	Mar. 25, 2012	Dec. 29, 2013 Segment	Dec. 30, 2012	Dec. 25, 2011
Segment Reporting Information [Line Items]
Number of principal business segments										2
Segment Reporting Information, Operating Income (Loss) [Abstract]
Service revenues										$ 443.6	$ 450.0	$ 351.0
Product sales										507.0	519.2	362.9
Total revenues		235.7	226.4	235.2	253.3	263.6	276.3	219.8	209.5	950.6	969.2	713.9
Depreciation and amortization										53.4	58.0	48.0
Total operating income (loss) from continuing operations		5.4	6.1	8.9	11.4	(80.3)	14.1	7.4	9.1	31.8	(49.7)	29.5
Revenue from foreign subsidiaries										100.9	116.2	54.3
Revenue from foreign subsidiaries, percentage										11.00%	12.00%	8.00%
Impairment of goodwill and intangible assets										0	96.6	0
Acquisition expenses (benefits)										(3.8)	(2.7)	12.5
Merger and acquisition related items						(2.7)	0.3	1.5	0.9	(2.0)
Settlement with one of the Company's D&O insurance carriers	3.1
Total assets		1,216.6				1,283.9				1,216.6	1,283.9
Assets of foreign subsidiaries		95.9				90.0				95.9	90.0
Trade names
Segment Reporting Information, Operating Income (Loss) [Abstract]
Intangible assets impairment charge											14.6
Kratos Government Solutions
Segment Reporting Information, Operating Income (Loss) [Abstract]
Service revenues										233.9	264.0	238.8
Product sales										507.0	519.2	362.9
Total revenues										740.9	783.2	601.7
Depreciation and amortization										49.9	54.5	45.7
Total operating income (loss) from continuing operations										26.4	(41.5)	35.4
Impairment of goodwill and intangible assets											83.7
Total assets		1,025.6				1,103.9				1,025.6	1,103.9
Kratos Government Solutions | Trade names
Segment Reporting Information, Operating Income (Loss) [Abstract]
Intangible assets impairment charge											1.7
Public Safety & Security
Segment Reporting Information, Operating Income (Loss) [Abstract]
Service revenues										209.7	186.0	112.2
Product sales										0	0	0
Total revenues										209.7	186.0	112.2
Depreciation and amortization										3.5	3.5	2.3
Total operating income (loss) from continuing operations										8.3	(2.5)	9.9
Total assets		122.6				106.8				122.6	106.8
Public Safety & Security | Trade names
Segment Reporting Information, Operating Income (Loss) [Abstract]
Intangible assets impairment charge											12.9
Discontinued operations
Segment Reporting Information, Operating Income (Loss) [Abstract]
Total assets		0				7.5				0	7.5
Corporate activities
Segment Reporting Information, Operating Income (Loss) [Abstract]
Total operating income (loss) from continuing operations										(2.9)	(5.7)	(15.8)
Total assets		$ 68.4				$ 65.7				$ 68.4	$ 65.7