Restructuring (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2016	Mar. 31, 2016	Jun. 30, 2015	Mar. 31, 2015	Jun. 30, 2016	Jun. 30, 2015
Restructuring Reserve [Roll Forward]
Beginning balance	$ 1.0	$ 0.0	$ 0.0	$ 0.0	$ 0.0	$ 0.0
Charge to expense	0.0	1.2	0.4	0.0	1.2	0.4
Cash payments	(0.8)	(0.2)	(0.1)	0.0
Ending balance	0.2	$ 1.0	0.3	$ 0.0	0.2	0.3
Operating Segments | Safety And Security Systems | Cost Reduction Plan
Restructuring Cost and Reserve [Line Items]
Severance costs					1.2
Expected additional restructuring charges	$ 2.0				$ 2.0
Operating Segments | Safety And Security Systems | Voluntary Reduction-In-Force Plan
Restructuring Cost and Reserve [Line Items]
Severance costs			$ 0.4			$ 0.4