XML 53 R42.htm IDEA: XBRL DOCUMENT v3.21.1
Stock-based Employee Compensation, Stock Option Plans, and Deferred Compensation Plan for Directors - Summary of Option Activity (Details) - USD ($)
 3 Months Ended
Mar. 31, 2021
Mar. 31, 2020
Number of Shares    
Outstanding at beginning of period (in shares) 1,502,670  
Granted (in shares) 0  
Exercised (in shares) 0  
Expired/Forfeited (in shares) (80,000)  
Outstanding at end of period (in shares) 1,422,670  
Exercisable at end of period (in shares) 924,045  
Weighted Average Exercise Price per share    
Outstanding at beginning of period (in usd per share) $ 52.86  
Granted (in usd per share) 0  
Exercised (in usd per share) 0  
Expired/Forfeited (in usd per share) 54.63  
Outstanding at end of period (in usd per share) 52.76  
Exercisable at end of period (in usd per share) $ 52.89  
Aggregate Intrinsic Value    
Outstanding at beginning of period $ 0  
Granted 0  
Exercised 0 $ 85,268
Expired/Forfeited 0  
Outstanding at end of period 12,337  
Exercisable at end of period $ 12,337