Segment Information (Details) (USD $) In Millions, unless otherwise specified	0 Months Ended	3 Months Ended		6 Months Ended			3 Months Ended		6 Months Ended			3 Months Ended		6 Months Ended			3 Months Ended		6 Months Ended						0 Months Ended
	Feb. 11, 2011	Jun. 24, 2012	Jun. 26, 2011	Jun. 24, 2012 Segment	Jun. 26, 2011	Dec. 25, 2011	Jun. 24, 2012 Kratos Government Solutions	Jun. 26, 2011 Kratos Government Solutions	Jun. 24, 2012 Kratos Government Solutions	Jun. 26, 2011 Kratos Government Solutions	Dec. 25, 2011 Kratos Government Solutions	Jun. 24, 2012 Public Safety and Security	Jun. 26, 2011 Public Safety and Security	Jun. 24, 2012 Public Safety and Security	Jun. 26, 2011 Public Safety and Security	Dec. 25, 2011 Public Safety and Security	Jun. 24, 2012 Unallocated corporate expense, net	Jun. 26, 2011 Unallocated corporate expense, net	Jun. 24, 2012 Unallocated corporate expense, net	Jun. 26, 2011 Unallocated corporate expense, net	Jun. 24, 2012 Discontinued operations	Dec. 25, 2011 Discontinued operations	Jun. 24, 2012 Corporate activities	Dec. 25, 2011 Corporate activities	May 14, 2012 Composite Engineering, Inc.
Segment Reporting Information [Line Items]
Proceeds from the issuance of common stock	$ 61.1			$ 97.0	$ 61.1																				$ 97.0
Number of principal business segments				2
Revenues		219.8	171.1	429.3	293.9		175.8	145.3	344.7	242.7		44.0	25.8	84.6	51.2
Operating income		7.4	8.7	16.5	10.1		8.8	9.7	18.4	16.3		2.8	1.7	4.0	2.9		(4.2)	(2.7)	(5.9)	(9.1)
Assets		$ 1,299.3		$ 1,299.3		$ 1,216.2	$ 1,014.4		$ 1,014.4		$ 1,029.0	$ 118.8		$ 118.8		$ 88.6					$ 8.1	$ 12.2	$ 158.0	$ 86.4
Common stock issued to fund purchase of CEI (shares)																									20.0