Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation (Summary of Restricted Stock Award and Unit Activity) (Details)

v3.10.0.1
Stock-Based Compensation (Summary of Restricted Stock Award and Unit Activity) (Details) - Restricted Stock
6 Months Ended
Jun. 30, 2018
$ / shares
shares
Number of Unvested Restricted Shares  
Unvested shares as of January 1, 2018 (in shares) | shares 976,027
Granted (in shares) | shares 1,197,628
Vested (in shares) | shares (301,017)
Forfeited (in shares) | shares (20,651)
Unvested shares as of June 30, 2018 (in shares) | shares 1,851,987
Weighted Average Grant Date Fair Value  
Unvested shares as of January 1, 2018 (in dollar per share) | $ / shares $ 18.71
Granted (in dollars per share) | $ / shares 9.45
Vested (in dollars per share) | $ / shares 14.41
Forfeited (in dollars per share) | $ / shares 17.87
Unvested shares as of June 30, 2018 (in dollars per share) | $ / shares $ 13.43