Acquisitions (2014 Acquisitions - Other 2014 Acquisitions) (Narrative) (Details) - USD ($) $ in Millions			9 Months Ended
	Apr. 01, 2014	Jan. 01, 2014	Sep. 30, 2015
April 2014 Acquisition [Member]
Business Combinations [Line Items]
Business combinations, effective date			Apr. 01, 2014
Business combinations, percentage of voting interests acquired			100.00%
Business combinations, description of acquired entity			a telecommunications services firm, specializing in the installation of in-home security systems
Business combinations, payments in cash (in dollars)	$ 16.3
April 2014 Acquisition [Member] | Earn-Out Arrangements [Member]
Business Combinations [Line Items]
Business combinations, contingent consideration, earn-out period (in years)			5 years
Business combinations, contingent consideration, fair value of earn-out (in dollars)			$ 0.6
January 2014 Acquisition [Member]
Business Combinations [Line Items]
Business combinations, effective date			Jan. 01, 2014
Business combinations, percentage of voting interests acquired			100.00%
Business combinations, description of acquired entity			a telecommunications services firm, specializing in the engineering, installation, furnishing and integration of telecommunications equipment
Business combinations, payments in cash (in dollars)		$ 23.8
January 2014 Acquisition [Member] | Earn-Out Arrangements [Member]
Business Combinations [Line Items]
Business combinations, contingent consideration, earn-out period (in years)			5 years
Business combinations, contingent consideration, fair value of earn-out (in dollars)			$ 8.7