Goodwill and Other Intangible Assets - Goodwill (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended			12 Months Ended			1 Months Ended	12 Months Ended			3 Months Ended	1 Months Ended
	Dec. 30, 2012	Dec. 29, 2013	Dec. 25, 2011	Dec. 30, 2012 Public Safety & Security	Dec. 29, 2013 Public Safety & Security	Dec. 25, 2011 Public Safety & Security	Jun. 30, 2012 Kratos Government Solutions	Dec. 30, 2012 Kratos Government Solutions	Dec. 29, 2013 Kratos Government Solutions	Dec. 25, 2011 Kratos Government Solutions	Jun. 24, 2012 Discontinued operations	Jun. 30, 2012 Discontinued operations Integral Systems, Inc.
Goodwill [Line Items]
Impairments	$ (82.0)			$ 0				$ (82.0)			$ (1.5)	$ (1.5)
Percentage by which goodwill fair value exceeded carrying value							7.40%
Goodwill [Roll Forward]
Balance as of December 25, 2011	596.5		571.6	35.6		33.0		560.9		538.6
Additions due to business combinations	106.9			2.6				104.3
Impairments	(82.0)			0				(82.0)			(1.5)	(1.5)
Retrospective adjustments	(0.1)			0				(0.1)
Balance as of December 30, 2012 after retrospective adjustments		596.4			35.6				560.8
Balance as of December 29, 2013	596.4	596.4		35.6	35.6			560.8	560.8
Accumulated impairment losses		$ 247.4			$ 18.3				$ 229.1