Discontinued Operations (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended				1 Months Ended
	Jun. 24, 2012	Jun. 26, 2011	Jun. 24, 2012	Jun. 26, 2011	Dec. 25, 2011	Aug. 02, 2010 Public Safety and Security	Jun. 30, 2012 Discontinued operations Integral Systems, Inc.
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Goodwill impairment charge associated with discontinued operations							$ 1.5
Sale proceeds (cash consideration and assumption of certain liabilities)						0.1
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Revenue	1.8	0	7.4	0
Net income (loss) before taxes	(2.3)	0.1	(2.9)	0.1
Benefit for income taxes	0	0	(0.1)	(0.3)
Net income (loss) after taxes	(2.3)	0.1	(2.8)	0.4
Disposal Group, Including Discontinued Operation, Balance Sheet Disclosures [Abstract]
Accounts receivable, net	2.2		2.2		5.3
Inventoried costs	4.4		4.4		4.0
Other current assets	0.7		0.7		0.4
Current assets of discontinued operations	7.3		7.3		9.7
Property and equipment, net	0.5		0.5		0.6
Goodwill	0		0		1.5
Other non-current assets	0.4		0.4		0.3
Non-current assets of discontinued operations	0.9		0.9		2.4
Accounts payable	4.5		4.5		3.0
Accrued expenses	1.7		1.7		1.5
Other current liabilities	0.3		0.3		1.8
Current liabilities of discontinued operations	6.5		6.5		6.3
Other non-current liabilities	0.4		0.4		0.5
Non-current liabilities of discontinued operations	$ 0.4		$ 0.4		$ 0.5