Share Based Compensation - Stock Options (Details)
6 Months Ended
Jun. 30, 2019
$ / shares
shares
Jun. 30, 2018
$ / shares
shares
Avgwtd grant-date fair value    
Exercised (in dollars per share) $ 3.23 $ 2.54
Avg wtd exercise price    
Exercised (in dollars per share) $ 4.30 $ 2.45
Units    
Exercised | shares (222,084) (5,000)
Stock options    
Avgwtd grant-date fair value    
Outstanding at the beginning of period $ 3.79 $ 3.66
Granted (in dollars per share)   6.51
Forfeited (in dollars per share) 6.51 6.26
Outstanding at the end of period 3.79 3.76
Vested (in dollars per share) 3.41 3.24
Nonvested (in dollars per share) 5.00 4.83
Avg wtd exercise price    
Outstanding at the beginning of period 6.12 5.71
Granted (in dollars per share)   14.25
Forfeited (in dollars per share) 14.26 13.73
Outstanding at the end of the period 6.13 6.04
Vested (in dollars per share) 4.98 4.46
Nonvested (in dollars per share) $ 9.79 $ 9.26
Units    
Outstanding at the beginning of period | shares 9,070,052 9,078,728
Granted (in shares) | shares   359,618
Forfeited (in shares) | shares (36,774) (7,682)
Outstanding at the end of the period | shares 8,811,194 9,425,664
Vested (in shares) | shares 6,691,308 6,331,146
Nonvested (in shares) | shares 2,119,886 3,094,518