Earnings Per Share - Additional Information (Details) shares in Millions |
3 Months Ended |
|---|---|
|
Mar. 31, 2018
shares
| |
| Stock option awards | |
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | |
| Anti-diluted shares excluded from computation of earnings per share (in shares) | 0.2 |
| Class C | Common Stock | |
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | |
| Anti-diluted shares excluded from computation of earnings per share (in shares) | 14.7 |