CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares |
Dec. 31, 2019 |
Dec. 31, 2018 |
|---|---|---|
| Common Class A | ||
| Class of Stock [Line Items] | ||
| Common stock, par value (in dollars per share) | $ 0.01 | $ 0.01 |
| Common stock, shares authorized (in shares) | 200,000,000 | 200,000,000 |
| Common stock shares issued (in shares) | 133,867,621 | 137,180,213 |
| Common stock shares outstanding (in shares) | 133,867,621 | 137,180,213 |
| Common Class B | ||
| Class of Stock [Line Items] | ||
| Common stock, par value (in dollars per share) | $ 0.01 | $ 0.01 |
| Common stock, shares authorized (in shares) | 75,000,000 | 75,000,000 |
| Common stock shares issued (in shares) | 4,045,199 | 4,045,199 |
| Common stock shares outstanding (in shares) | 4,045,199 | 4,045,199 |
| Common Class C | ||
| Class of Stock [Line Items] | ||
| Common stock, par value (in dollars per share) | $ 0.01 | $ 0.01 |
| Common stock, shares authorized (in shares) | 50,000,000 | 50,000,000 |
| Common stock shares issued (in shares) | 0 | 0 |
| Common stock shares outstanding (in shares) | 0 | 0 |