Restructuring (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Restructuring Reserve [Roll Forward]
Beginning balance			$ 0.4	$ 0.0
Charge to expense	$ 0.1	$ 0.4	0.5	1.6
Cash payments			(0.7)	(1.2)
Ending balance	0.2	0.4	0.2	0.4
Operating Segments | Safety & Security Systems | Facility Closing [Member]
Restructuring Reserve [Roll Forward]
Charge to expense	$ 0.1		$ 0.5
Operating Segments | Safety & Security Systems | Voluntary Reduction-In-Force Plan
Restructuring Cost and Reserve [Line Items]
Severance costs		$ 0.4		1.6
Restructuring Reserve [Roll Forward]
Charge to expense				$ 1.6