XML 142 R97.htm IDEA: XBRL DOCUMENT v3.8.0.1
Stockholders' Equity - Restricted and Performance Stock Activity (Details)
12 Months Ended
Dec. 31, 2017
$ / shares
shares
Shares  
Unvested, shares beginning of period (in shares) 922,900
Granted (in shares) 627,046
Vested (in shares) (824,722)
Forfeited (in shares) (146,830)
Unvested, shares end of period (in shares) 578,394
Weighted Average Grant Date Fair Value  
Unvested, weighted average grant date fair value beginning balance (USD per share) | $ / shares $ 58.15
Granted (USD per share) | $ / shares 57.34
Vested (USD per share) | $ / shares 57.78
Forfeited (USD per share) | $ / shares 53.89
Unvested, weighted average grant date fair value ending balance (USD per share) | $ / shares $ 58.35
Restricted Stock Awards  
Shares  
Unvested, shares beginning of period (in shares) 577,244
Granted (in shares) 395,946
Vested (in shares) (424,556)
Forfeited (in shares) (146,830)
Unvested, shares end of period (in shares) 401,804
Performance Stock Awards  
Shares  
Unvested, shares beginning of period (in shares) 345,656
Granted (in shares) 0
Vested (in shares) (260,894)
Forfeited (in shares) 0
Unvested, shares end of period (in shares) 84,762
Performance Stock Units  
Shares  
Unvested, shares beginning of period (in shares) 0
Granted (in shares) 231,100
Vested (in shares) (139,272)
Forfeited (in shares) 0
Unvested, shares end of period (in shares) 91,828