Stockholders' Equity - Common Stock (Details) - USD ($) $ / shares in Units, $ in Millions		12 Months Ended
Mar. 07, 2017	Dec. 31, 2017
Class of Stock [Line Items]
Net proceeds used to pay-off debt		$ 240.4
Common Stock
Class of Stock [Line Items]
Common stock sold (in shares)	15,525,000,000,000
Purchase price of common stock sold (dollars per share)	$ 16.25
Gross proceeds from sell of stock		$ 252.3

Number of new stock issued during the period.

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