Annual report pursuant to Section 13 and 15(d)

Stock-Based Compensation - Schedule of Activity Related to PSAs, PSUs, and RSUs (Details)

v3.8.0.1
Stock-Based Compensation - Schedule of Activity Related to PSAs, PSUs, and RSUs (Details)
12 Months Ended
Dec. 31, 2017
$ / shares
shares
PSAs and PSUs  
Number of Shares (in thousands)  
Outstanding at beginning of period (in shares) | shares 801,900
Granted (in shares) | shares 317,800
Vested (in shares) | shares (50,300)
Forfeited (in shares) | shares (176,700)
Outstanding at end of period (in shares) | shares 892,700
Weighted-Average Grant-Date Fair Value (per share)  
Outstanding at beginning of period (in dollars per share) | $ / shares $ 12.88
Granted (in dollars per share) | $ / shares 16.54
Vested (in dollars per share) | $ / shares 14.63
Forfeited (in dollars per share) | $ / shares 13.62
Outstanding at end of period (in dollars per share) | $ / shares $ 13.93
RSUs  
Number of Shares (in thousands)  
Outstanding at beginning of period (in shares) | shares 362,800
Granted (in shares) | shares 121,000
Vested (in shares) | shares (213,600)
Forfeited (in shares) | shares (38,600)
Outstanding at end of period (in shares) | shares 231,600
Weighted-Average Grant-Date Fair Value (per share)  
Outstanding at beginning of period (in dollars per share) | $ / shares $ 14.56
Granted (in dollars per share) | $ / shares 17.21
Vested (in dollars per share) | $ / shares 14.68
Forfeited (in dollars per share) | $ / shares 14.98
Outstanding at end of period (in dollars per share) | $ / shares $ 15.77