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Stockholders' Equity (Details) | Sep. 30, 2019 vote $ / shares shares | Dec. 31, 2018 $ / shares shares
--- | --- | ---
Class of Stock [Line Items] |  |
Common stock, shares, outstanding | 77,802,278 | 76,942,872
Unvested - Number of awards (in shares) | 5,006,649 | 4,678,457
Class A Common Stock |  |
Class of Stock [Line Items] |  |
Common stock, par value per share (in dollars per share) | $ / shares | $ 0.01 | $ 0.01
Common stock, shares authorized (in shares) | 500,000,000 | 500,000,000
Common stock, shares, outstanding | 56,261,026 |
Common stock votes per share | vote | 1 |
Class B Common Stock |  |
Class of Stock [Line Items] |  |
Common stock, par value per share (in dollars per share) | $ / shares | $ 0.01 | $ 0.01
Common stock, shares authorized (in shares) | 200,000,000 | 200,000,000
Common stock, shares, outstanding | 7,853,364 | 8,645,249
Common stock votes per share | vote | 1 |
Class C Common Stock |  |
Class of Stock [Line Items] |  |
Common stock, par value per share (in dollars per share) | $ / shares | $ 0.01 | $ 0.01
Common stock, shares authorized (in shares) | 400,000,000 | 400,000,000
Common stock, shares, outstanding | 13,687,888 | 14,226,435
Common stock votes per share | vote | 1 |
Restricted Stock | Holdings GP Units |  |
Class of Stock [Line Items] |  |
Unvested - Number of awards (in shares) | 4,899,524 |

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