Business Combinations, Intangible Assets Acquired (Details) $ in Millions	3 Months Ended
	Mar. 31, 2016 USD ($)
Intangible Assets Acquired [Abstract]
Aggregate acquisitions	$ 20.1
Customer Relationships [Member]
Intangible Assets Acquired [Abstract]
Weighted average useful life	7 years
Aggregate acquisitions	$ 18.4
Customer Relationships [Member] | Minimum [Member]
Intangible Assets Acquired [Abstract]
Useful life	5 years
Customer Relationships [Member] | Maximum [Member]
Intangible Assets Acquired [Abstract]
Useful life	8 years
Customer Backlog [Member]
Intangible Assets Acquired [Abstract]
Weighted average useful life	10 months
Aggregate acquisitions	$ 1.4
Customer Backlog [Member] | Minimum [Member]
Intangible Assets Acquired [Abstract]
Useful life	9 months
Customer Backlog [Member] | Maximum [Member]
Intangible Assets Acquired [Abstract]
Useful life	12 months
Non-Compete Agreements [Member]
Intangible Assets Acquired [Abstract]
Weighted average useful life	5 years
Useful life	5 years
Aggregate acquisitions	$ 0.1
Trade Name [Member]
Intangible Assets Acquired [Abstract]
Weighted average useful life	1 year
Useful life	1 year
Aggregate acquisitions	$ 0.2