Annual report pursuant to Section 13 and 15(d)

Stock-Based Compensation - Summary of Exercise Price for Stock Options Outstanding and Exercisable (Details)

v3.21.4
Stock-Based Compensation - Summary of Exercise Price for Stock Options Outstanding and Exercisable (Details) - $ / shares
Sep. 30, 2021
Sep. 30, 2020
Sep. 30, 2019
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]      
Number of options outstanding 87,500 119,168 200,418
Option exercise price outstanding $ 18.81 $ 15.76 $ 16.37
Number of options exercisable 78,500 95,001  
Option exercise price exercisable $ 16.29 $ 15.50  
$10.00      
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]      
Number of options outstanding 25,000    
Option exercise price outstanding $ 10.00    
Number of options exercisable 25,000    
Option exercise price exercisable $ 10.00    
$12.50      
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]      
Number of options outstanding 6,250    
Option exercise price outstanding $ 12.50    
Number of options exercisable 6,250    
Option exercise price exercisable $ 12.50    
$15.00      
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]      
Number of options outstanding 6,250    
Option exercise price outstanding $ 15.00    
Number of options exercisable 6,250    
Option exercise price exercisable $ 15.00    
$15.18      
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]      
Number of options outstanding 25,000    
Option exercise price outstanding $ 15.18    
Number of options exercisable 25,000    
Option exercise price exercisable $ 15.18    
$23.41      
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]      
Number of options outstanding 4,000    
Option exercise price outstanding $ 23.41    
Number of options exercisable 4,000    
Option exercise price exercisable $ 23.41    
$27.60      
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]      
Number of options outstanding 4,000    
Option exercise price outstanding $ 27.60    
Number of options exercisable 4,000    
Option exercise price exercisable $ 27.60    
$31.74      
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]      
Number of options outstanding 4,000    
Option exercise price outstanding $ 31.74    
Number of options exercisable 4,000    
Option exercise price exercisable $ 31.74    
$36.50      
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]      
Number of options outstanding 4,000    
Option exercise price outstanding $ 36.50    
Number of options exercisable 4,000    
Option exercise price exercisable $ 36.50    
$40.00      
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]      
Number of options outstanding 5,000    
Option exercise price outstanding $ 40.00    
$41.98      
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]      
Number of options outstanding 4,000    
Option exercise price outstanding $ 41.98