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Stockholders' Equity - Additional Information (Details) - USD ($) $ / shares in Units, shares in Millions |  | 12 Months Ended |
--- | --- | --- | ---
May 05, 2017 | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | Jan. 23, 2019
Class of Stock [Line Items] |  |  |  |  |
Common stock, shares authorized (in shares) |  | 1,125.0 | 1,125.0 |  |
Common stock, par value (in dollars per share) |  | $ 0.20 | $ 0.20 |  |
Common stock shares outstanding (in shares) |  | 436.0 |  |  |
Common shares unissued but encumbered (in shares) |  | 41.0 |  |  |
Common stock dividends |  | $ 0 | $ 0 | $ 0 |
Series A Preferred Stock |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |
Preferred stock shares outstanding (in shares) | 3.3 |  |  |  |
Preferred stock dividend rate (as a percentage) |  | 6.97% |  |  |
Preferred stock dividend rate (in dollars per share) | $ 50 |  |  |  |
Series B Preferred Stock |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |
Preferred stock shares outstanding (in shares) |  | 4.0 | 4.0 |  |
Preferred stock liquidation preference (in dollars per share) |  | $ 100 |  |  |
Common Stock |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |
Share price (in dollars per share) |  | $ 8.31 |  |  |
Three Month LIBOR | Series B Preferred Stock |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |
Preferred stock dividend rate (as a percentage) |  | 1.70% |  |  |
Subsequent Event |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |
Stock Repurchase Program, Authorized Amount |  |  |  |  | $ 200,000,000

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