Goodwill and Intangible Assets - Intangible Assets (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014
Definite-Lived Intangible Assets [Roll Forward]
Beginning Balance		$ 1.9
Additions	[1]	70.4
Amortization		(4.0)
Other	[2]	(0.3)
Ending Balance		68.0
Intangible Assets [Abstract]
Total Intangible Assets		84.6	$ 1.9
Total Intangible Assets, Additions	[1]	87.0
Total Intangible Assets, Amortization		(4.0)
Total Intangible Assets, Other	[2]	(0.3)
Accumulated Amortization		4.1	$ 0.1
Definite-Lived Intangible Assets, Estimated Annual Amortization Expense [Abstract]
2016		5.1
2017		5.0
2018		4.7
2019		4.4
2020		4.2
Thereafter		$ 44.6
Minimum [Member]
Intangible Assets [Abstract]
Useful Life (Years)		3 years
Maximum [Member]
Intangible Assets [Abstract]
Useful Life (Years)		22 years
Weighted Average [Member]
Intangible Assets [Abstract]
Useful Life (Years)		21 years
Trademarks and Trade Names [Member]
Indefinite-Lived Intangible Assets [Roll Forward]
Beginning Balance		$ 0.0
Additions	[1]	16.6
Other	[2]	0.0
Ending Balance		16.6
Customer Relationships [Member]
Definite-Lived Intangible Assets [Roll Forward]
Beginning Balance		0.0
Additions	[1]	64.0
Amortization		(3.2)
Other	[2]	0.0
Ending Balance		60.8
Intangible Assets [Abstract]
Total Intangible Assets, Amortization		$ (3.2)
Useful Life (Years)		22 years
Developed Technology and Other [Member]
Definite-Lived Intangible Assets [Roll Forward]
Beginning Balance	[3]	$ 1.9
Additions	[1],[3]	6.4
Amortization	[3]	(0.8)
Other	[2],[3]	(0.3)
Ending Balance	[3]	7.2
Intangible Assets [Abstract]
Total Intangible Assets, Amortization	[3]	$ (0.8)
Developed Technology and Other [Member] | Minimum [Member]
Intangible Assets [Abstract]
Useful Life (Years)		3 years
Developed Technology and Other [Member] | Maximum [Member]
Intangible Assets [Abstract]
Useful Life (Years)		13 years
Developed Technology and Other [Member] | Weighted Average [Member]
Intangible Assets [Abstract]
Useful Life (Years)		9 years

[1] Additions are primarily the result of the U.S. Water Services acquisition. (See Note 7. Acquisitions.)

[2] Armenia Mountain was acquired on July 1, 2015, at which time the purchase option intangible asset was reclassified as a component of the acquisition consideration.

[3] Developed Technology and Other includes patents, non-compete agreements, and land easements.