v3.8.0.1
Stock Incentive Plans - Non-Vested Restricted Stock And Restricted Stock (Details)
shares in Thousands
12 Months Ended
Dec. 31, 2017
$ / shares
shares
Shares  
Non-vested balance as of beginning of period (in shares) | shares 4,790
Granted (in shares) | shares 1,412
Vested (in shares) | shares (1,883)
Forfeited (in shares) | shares (150)
Non-vested balance as of end of period (in shares) | shares 4,169
Weighted Average Grant Date Fair Value  
Non-vested balance as of beginning of period (usd per share) | $ / shares $ 55.75
Granted (usd per share) | $ / shares 95.13
Vested (usd per share) | $ / shares 58.10
Forfeited (usd per share) | $ / shares 20.40
Non-vested balance as of end of period (usd per share) | $ / shares $ 69.30