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Goodwill and Intangible Assets - Intangible Assets (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Definite-Lived Intangible Assets [Roll Forward] |  |  |  |
Beginning Balance |  | $ 61.0 |  |
Additions |  | 2.8 |  |
Amortization |  | (5.6) | $ (5.5) | $ (5.2)
Ending Balance |  | 58.2 | 61.0 |
Definite-Lived Intangible Assets, Estimated Annual Amortization Expense [Abstract] |  |  |  |
2019 |  | 5.3 |  |
2020 |  | 4.9 |  |
2021 |  | 4.9 |  |
2022 |  | 4.6 |  |
2023 |  | 4.3 |  |
Thereafter |  | 34.2 |  |
Intangible Assets [Abstract] |  |  |  |
Total Intangible Assets |  | 74.8 | 77.6 |
Total Intangible Assets, Additions |  | 2.8 |  |
Total Intangible Assets, Amortization |  | (5.6) | (5.5) | $ (5.2)
Accumulated Amortization |  | $ 20.4 | 14.8 |
Weighted Average [Member] |  |  |  |
Definite-Lived Intangible Assets [Roll Forward] |  |  |  |
Useful Life (Years) |  | 6 years |  |
Trademarks and Trade Names [Member] |  |  |  |
Indefinite-Lived Intangible Assets [Roll Forward] |  |  |  |
Beginning Balance |  | $ 16.6 |  |
Additions |  | 0.0 |  |
Ending Balance |  | 16.6 | 16.6 |
Customer Relationships [Member] |  |  |  |
Definite-Lived Intangible Assets [Roll Forward] |  |  |  |
Beginning Balance |  | 54.7 |  |
Additions |  | 0.2 |  |
Amortization |  | (4.2) |  |
Ending Balance |  | $ 50.7 | 54.7 |
Useful Life (Years) |  | 19 years |  |
Intangible Assets [Abstract] |  |  |  |
Total Intangible Assets, Amortization |  | $ (4.2) |  |
Developed Technology and Other [Member] |  |  |  |
Definite-Lived Intangible Assets [Roll Forward] |  |  |  |
Beginning Balance | [1] | 6.3 |  |
Additions | [1] | 2.6 |  |
Amortization | [1] | (1.4) |  |
Ending Balance | [1] | 7.5 | $ 6.3 |
Intangible Assets [Abstract] |  |  |  |
Total Intangible Assets, Amortization | [1] | $ (1.4) |  |
Developed Technology and Other [Member] | Minimum [Member] |  |  |  |
Definite-Lived Intangible Assets [Roll Forward] |  |  |  |
Useful Life (Years) |  | 4 years |  |
Developed Technology and Other [Member] | Maximum [Member] |  |  |  |
Definite-Lived Intangible Assets [Roll Forward] |  |  |  |
Useful Life (Years) |  | 10 years |  |
Developed Technology and Other [Member] | Weighted Average [Member] |  |  |  |
Definite-Lived Intangible Assets [Roll Forward] |  |  |  |
Useful Life (Years) |  | 17 years |  |
[1] | Developed Technology and Other includes patents, non-compete agreements, land easements and trade names with finite lives.

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