Acquisitions (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended			3 Months Ended		3 Months Ended		6 Months Ended	9 Months Ended							9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011	Jun. 30, 2012 IronKey Systems Inc.	Oct. 04, 2011 IronKey Systems Inc.	Sep. 30, 2012 MXI Security	Jun. 30, 2012 MXI Security	Jun. 30, 2012 MXI Security	Sep. 30, 2012 MXI Security	Jun. 04, 2011 MXI Security	Sep. 30, 2012 MXI Security Minimum Second Earn-out Payment	Jun. 30, 2012 MXI Security Maximum First and Second Earn-out Payment [Member]	Sep. 30, 2012 MXI Security Maximum Second Earn-out Payment	Jun. 30, 2012 MXI Security Maximum Second Earn-out Payment	Jun. 30, 2012 MXI Security Maximum Third Earn-out Payment [Member] [Domain]	Sep. 30, 2012 BeCompliant Corporation (Encryptx)	Feb. 28, 2011 BeCompliant Corporation (Encryptx)
Business Acquisition, Contingent Consideration [Line Items]
Cash paid to acquired entity							$ 19.0
Purchase price adjustment						0.6
Contingent consideration maximum range outcome												45.0
Earn-out payments	0.9		0.9		9.2								0	25.0	25.0	25.0	20.0		0.7
Contingent consideration fair value								0.9	6.4	6.4	0.9	9.2							1.3
Contingent consideration adjustment	(5.5)	0	(8.3)	0				(5.5)	(2.8)	(2.8)	(8.3)
Contingent consideration payments			$ (1.2)	$ 0														$ (0.7)