Acquisitions - SecureInfo Corporation (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended			3 Months Ended	9 Months Ended				0 Months Ended
	Sep. 30, 2012	Sep. 25, 2011	Sep. 30, 2012	Sep. 25, 2011	Dec. 25, 2011	Sep. 30, 2012 SecureInfo Corporation	Sep. 30, 2012 SecureInfo Corporation	Nov. 15, 2011 SecureInfo Corporation	Nov. 15, 2011 SecureInfo Corporation Earnout	Nov. 15, 2011 SecureInfo Corporation Holdback escrow	Nov. 15, 2011 SecureInfo Corporation Purchase price adjustment
Business Acquisition, Cost of Acquired Entity [Abstract]
Purchase price								$ 20.3
Contingent consideration, fair value	3.1		3.1		7.6				1.5	1.8
Closing working capital cutoff											2.2
Closing working capital, actual											2.1
Working capital adjustment											0.1
Business Combination, Acquired Receivables [Abstract]
Acquired accounts receivable, gross								2.9
Revenues	276.3	206.6	705.6	500.5		4.6	12.3
Operating income (loss)	$ 14.1	$ 9.7	$ 30.6	$ 19.8		$ (0.2)	$ 0.2