Goodwill and Intangible Assets - Intangible Assets (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Definite-Lived Intangible Assets [Roll Forward]
Beginning Balance				$ 65.6
Additions	[1]			0.9
Amortization		$ (1.3)	$ (1.3)	(4.1)	$ (3.8)
Ending Balance		62.4		62.4
Accumulated Amortization		13.4		13.4		$ 9.3
Estimated Annual Amortization Expense for Definite-Lived Intangible Assets [Abstract]
Remainder of 2017		1.5		1.5
2018		5.3		5.3
2019		4.9		4.9
2020		4.7		4.7
2021		4.6		4.6
Thereafter		41.4		41.4
Intangible Assets [Abstract]
Total Intangible Assets		79.0		79.0		$ 82.2
Total Intangible Assets, Additions	[2]			0.9
Total Intangible Assets, Amortization		(1.3)	$ (1.3)	$ (4.1)	$ (3.8)
Weighted Average [Member]
Definite-Lived Intangible Assets [Roll Forward]
Remaining Useful Life (Years)				19 years
Trademarks and Trade Names [Member]
Indefinite-Lived Intangible Assets [Roll Forward]
Beginning Balance				$ 16.6
Additions	[2]			0.0
Ending Balance		16.6		16.6
Customer Relationships [Member]
Definite-Lived Intangible Assets [Roll Forward]
Beginning Balance				59.3
Additions	[2]			0.0
Amortization				(3.4)
Ending Balance		55.9		$ 55.9
Remaining Useful Life (Years)				20 years
Intangible Assets [Abstract]
Total Intangible Assets, Amortization				$ (3.4)
Developed Technology and Other [Member]
Definite-Lived Intangible Assets [Roll Forward]
Beginning Balance	[1]			6.3
Additions	[1],[2]			0.9
Amortization	[1]			(0.7)
Ending Balance	[1]	$ 6.5		6.5
Intangible Assets [Abstract]
Total Intangible Assets, Amortization	[1]			$ (0.7)
Developed Technology and Other [Member] | Minimum [Member]
Definite-Lived Intangible Assets [Roll Forward]
Remaining Useful Life (Years)				1 year
Developed Technology and Other [Member] | Maximum [Member]
Definite-Lived Intangible Assets [Roll Forward]
Remaining Useful Life (Years)				11 years
Developed Technology and Other [Member] | Weighted Average [Member]
Definite-Lived Intangible Assets [Roll Forward]
Remaining Useful Life (Years)				7 years

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

[2] Additions resulting from the September 1, 2017, acquisition of Tonka Water. (See Note 3. Acquisitions.)