Annual report pursuant to Section 13 and 15(d)

Stock Options, Stock Grants and New Stock Issues - Narrative (Details)

v3.19.1
Stock Options, Stock Grants and New Stock Issues - Narrative (Details)
12 Months Ended
May 17, 2018
USD ($)
shares
Feb. 07, 2018
$ / shares
shares
May 18, 2017
USD ($)
shares
Feb. 08, 2017
employees
$ / shares
shares
May 05, 2016
USD ($)
employees
$ / shares
shares
Feb. 19, 2016
$ / shares
shares
Feb. 10, 2015
$ / shares
shares
Dec. 31, 2018
USD ($)
$ / shares
shares
Dec. 31, 2017
USD ($)
$ / shares
shares
Dec. 31, 2016
USD ($)
$ / shares
shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Options granted, weighted average fair value (dollars per share) | $ / shares               $ 6.44 $ 6.41 $ 6.24
Exercised (shares)               85,440 25,632  
Shares of common stock purchased (shares)                   29,500
Options exercisable (shares)               49,127    
Options exercisable, weighted average exercise price (dollars per share) | $ / shares               $ 13.82    
Share-based compensation expense | $               $ 826,998 $ 638,416 $ 459,473
Issuance of shares of common stock from the treasury (shares)               66,632 58,532 62,124
Stock Options                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Exercised (shares)               85,440 25,632 0
Option exercises, aggregate exercise price | $               $ 1,033,110 $ 296,050  
Shares of common stock purchased (shares)               10,578    
Cash received from previous employees | $               $ 141,855    
Options exercisable (shares)               49,127 119,861 129,762
Options exercisable, weighted average exercise price (dollars per share) | $ / shares               $ 13.82 $ 12.45 $ 12.12
Share-based compensation expense | $               $ 46,529 $ 80,966 $ 135,085
Total unrecognized compensation cost | $               $ 36,420    
Share-based compensation, weighted average period of recognition               1 year 21 days    
2011 Plan | Stock Options                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Options granted (shares)             32,532      
Options granted, weighted average exercise price (dollars per share) | $ / shares             $ 16.01      
Options granted, weighted average fair value (dollars per share) | $ / shares             $ 6.39      
Risk free interest rate             2.00%      
Expected life             7 years      
Expected volatility rate             46.00%      
Expected dividend yield             2.00%      
2005 Stock Awards Plan | Stock Options                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Annual vesting rate               20.00%    
2005 Stock Awards Plan | Stock Awards                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Share-based compensation expense | $               $ 780,469 557,450 324,388
Total unrecognized compensation cost | $               $ 1,077,095    
Share-based compensation, weighted average period of recognition               1 year 10 months 16 days    
Share-based compensation expense, period of recognition (years)               60 months    
Share-based compensation expense, net of taxes | $               $ 616,571 $ 354,538 $ 206,311
Share-based compensation expense, net of taxes, (dollars per share) | $ / shares               $ 0.07 $ 0.04 $ 0.02
2015 Stock Awards Plan | Stock Awards                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Annual vesting rate               20.00%    
Number of shares authorized (shares)               250,000    
Expiration period for awards               10 years    
Period after grant date, awards vesting begins               1 year    
Granted (shares)   65,527   44,687 42,193 50,062        
Granted, weighted average grant date fair value (dollars per share) | $ / shares   $ 12.47   $ 12.30 $ 8.05 $ 7.51        
Vesting period       3 years 5 years          
Number of employees receiving grants | employees       8 5          
2015 Stock Awards Plan | Stock Awards | Minimum                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Annual vesting rate               20.00%    
Number of shares authorized (shares) 250,000                  
2015 Stock Awards Plan | Stock Awards | Maximum                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Annual vesting rate               33.00%    
Number of shares authorized (shares) 500,000                  
Non Employee Director                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Issuance of shares of common stock from the treasury (shares) 14,857   24,209   40,991          
Annual cash retainer fees | $ $ 276,000   $ 287,500   $ 330,000          
Restricted Stock | Non Employee Director                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Maximum annual retainer percent               100.00%    
May 5, 2016 | 2015 Stock Awards Plan | Stock Awards                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Share-based compensation expense | $               $ 75,756    
February 8, 2017 | 2015 Stock Awards Plan | Stock Awards                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Share-based compensation expense | $               $ 67,180