Business Acquisitions - Narrative (Details) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($) acquisition	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)
Business Acquisition [Line Items]
Goodwill			$ 1,063.5		$ 991.0
Cash used for acquisitions			$ 110.3	$ 172.5
Power
Business Acquisition [Line Items]
Number of businesses acquired | acquisition		2
Consideration transferred		$ 9.5
Intangible assets		3.4
Goodwill		$ 4.5
Intangible assets, useful life		13 years
Tax deductible goodwill		$ 2.7
iDevices
Business Acquisition [Line Items]
Consideration transferred	$ 59.2
Intangible assets	9.6
Goodwill	$ 45.3
Intangible assets, useful life	12 years
AEC
Business Acquisition [Line Items]
Consideration transferred	$ 31.6
Intangible assets	16.8
Goodwill	$ 12.1
Intangible assets, useful life	18 years