Earnings Per Share (Details) - shares shares in Thousands |
9 Months Ended | 12 Months Ended |
---|---|---|
Sep. 30, 2018 |
Dec. 31, 2017 |
|
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||
Antidilutive common stock instruments outstanding (shares) | 8,248 | 7,352 |
Shares issuable upon the release of restricted stock awards | ||
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||
Antidilutive common stock instruments outstanding (shares) | 66 | 24 |
Shares issuable upon exercise of stock options | ||
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||
Antidilutive common stock instruments outstanding (shares) | 8,182 | 7,328 |