Annual report pursuant to Section 13 and 15(d)

Stockholders' Equity - Share Grants Activity (Details)

v3.20.4
Stockholders' Equity - Share Grants Activity (Details) - $ / shares
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Weighted average grant date fair value      
Granted (in dollars per share) $ 123.89 $ 110.56 $ 64.11
Nonvested stock      
Number of Shares      
Share grants outstanding, beginning balance (in shares) 534,331    
Granted (in shares) 136,245    
Vested or exercised (in shares) (200,945)    
Forfeited (in shares) 0    
Share grants outstanding, ending balance (in shares) 469,631 534,331  
Weighted average grant date fair value      
Share grants outstanding, beginning balance (in dollars per share) $ 71.01    
Granted (in dollars per share) 123.89    
Vested or exercised (in dollars per share) 128.85    
Forfeited (in dollars per share) 0    
Share grants outstanding, ending balance (in dollars per share) $ 89.69 $ 71.01  
Options      
Number of Shares      
Share grants outstanding, beginning balance (in shares) 98,756    
Granted (in shares) 0    
Vested or exercised (in shares) (16,286)    
Forfeited Shares (in shares) (8,235)    
Share grants outstanding, ending balance (in shares) 74,235 98,756  
Weighted average grant date fair value      
Share grants outstanding, beginning balance (in dollars per share) $ 40.71    
Granted (in dollars per share) 0    
Vested or exercised (in dollars per share) 32.93    
Forfeited Shares (in dollars per share) 43.86    
Share grants outstanding, ending balance (in dollars per share) $ 42.07 $ 40.71