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Business and Basis of Presentation - Special Distribution, Corporate Conversion and Initial Public Offering (Details) - USD ($) $ / shares in Units, $ in Millions | Apr. 19, 2017 | Mar. 31, 2017 | Sep. 30, 2017 | Apr. 12, 2017 | Dec. 31, 2016
--- | --- | --- | --- | --- | ---
Class of Stock [Line Items] |  |  |  |  |
Cash distributions paid |  | $ 190.0 |  |  |
Common stock shares authorized (in shares) |  |  | 140,000,000 | 140,000,000 | 140,000,000
Common stock par value (in dollars per share) |  |  | $ 0.01 | $ 0.01 | $ 0.01
Preferred stock shares authorized (in shares) |  |  | 10,000,000 | 10,000,000 | 10,000,000
Preferred stock par value (in dollars per share) |  |  | $ 0.01 | $ 0.01 | $ 0.01
Common stock shares outstanding (in shares) |  |  | 53,446,284 |  | 53,442,532
Common Stock | IPO |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |
Stock issued during period (in shares) | 16,666,667 |  |  |  |
Shares issued (in dollars per share) | $ 19.00 |  |  |  |
Proceeds from issuance of common stock | $ 296.9 |  |  |  |
Stock issuance costs | 19.8 |  |  |  |
Payments of stock issuance costs | $ 15.9 |  |  |  |
Common stock shares outstanding (in shares) | 53,442,532 |  |  |  |

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