Goodwill and Intangible Assets - Intangible Assets (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Definite-Lived Intangible Assets [Roll Forward]
Beginning Balance		$ 68.0
Additions	[1]	2.8
Amortization		(5.2)	$ (4.0)	$ (0.1)
Ending Balance		65.6	68.0
Definite-Lived Intangible Assets, Estimated Annual Amortization Expense [Abstract]
2017		5.5
2018		5.1
2019		4.8
2020		4.5
2021		4.4
Thereafter		41.3
Intangible Assets [Abstract]
Total Intangible Assets		82.2	84.6
Total Intangible Assets, Additions	[1]	2.8
Total Intangible Assets, Amortization		(5.2)	(4.0)	$ (0.1)
Accumulated Amortization		$ 9.3	4.1
Minimum [Member]
Definite-Lived Intangible Assets [Roll Forward]
Useful Life (Years)		2 years
Maximum [Member]
Definite-Lived Intangible Assets [Roll Forward]
Useful Life (Years)		21 years
Weighted Average [Member]
Definite-Lived Intangible Assets [Roll Forward]
Useful Life (Years)		20 years
Trademarks and Trade Names [Member]
Indefinite-Lived Intangible Assets [Roll Forward]
Beginning Balance		$ 16.6
Additions	[1]	0.0
Ending Balance		16.6	16.6
Customer Relationships [Member]
Definite-Lived Intangible Assets [Roll Forward]
Beginning Balance		60.8
Additions	[1]	2.8
Amortization		(4.3)
Ending Balance		$ 59.3	60.8
Useful Life (Years)		21 years
Intangible Assets [Abstract]
Total Intangible Assets, Amortization		$ (4.3)
Developed Technology and Other [Member]
Definite-Lived Intangible Assets [Roll Forward]
Beginning Balance	[2]	7.2
Additions	[1],[2]	0.0
Amortization	[2]	(0.9)
Ending Balance	[2]	6.3	$ 7.2
Intangible Assets [Abstract]
Total Intangible Assets, Amortization	[2]	$ (0.9)
Developed Technology and Other [Member] | Minimum [Member]
Definite-Lived Intangible Assets [Roll Forward]
Useful Life (Years)		2 years
Developed Technology and Other [Member] | Maximum [Member]
Definite-Lived Intangible Assets [Roll Forward]
Useful Life (Years)		12 years
Developed Technology and Other [Member] | Weighted Average [Member]
Definite-Lived Intangible Assets [Roll Forward]
Useful Life (Years)		8 years

[1] Additions resulting from the October 11, 2016, acquisition of WEST. (See Note 6. Acquisitions.)

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