Annual report pursuant to Section 13 and 15(d)

Stock Options, Stock Grants and New Stock Issues - Stock Options by Exercise Price Range (Details)

v3.19.1
Stock Options, Stock Grants and New Stock Issues - Stock Options by Exercise Price Range (Details)
12 Months Ended
Dec. 31, 2018
$ / shares
shares
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Number of outstanding stock options (shares) | shares 59,096
Number of exercisable stock options (shares) | shares 49,127
$11.35  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Range of exercise prices (dollars per share) $ 11.35
Number of outstanding stock options (shares) | shares 13,402
Weighted average exercise price (dollars per share) $ 11.35
Weighted average remaining contractual life in years 3 years 1 month 6 days
Number of exercisable stock options (shares) | shares 13,402
Exercisable stock options, weighted average exercise price (dollars per share) $ 11.35
$13.70  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Range of exercise prices (dollars per share) $ 13.70
Number of outstanding stock options (shares) | shares 15,933
Weighted average exercise price (dollars per share) $ 13.70
Weighted average remaining contractual life in years 4 years 1 month 6 days
Number of exercisable stock options (shares) | shares 15,933
Exercisable stock options, weighted average exercise price (dollars per share) $ 13.70
$14.76  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Range of exercise prices (dollars per share) $ 14.76
Number of outstanding stock options (shares) | shares 8,109
Weighted average exercise price (dollars per share) $ 14.76
Weighted average remaining contractual life in years 5 years 1 month 20 days
Number of exercisable stock options (shares) | shares 6,643
Exercisable stock options, weighted average exercise price (dollars per share) $ 14.76
$16.01  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Range of exercise prices (dollars per share) $ 16.01
Number of outstanding stock options (shares) | shares 21,652
Weighted average exercise price (dollars per share) $ 16.01
Weighted average remaining contractual life in years 6 years 1 month 9 days
Number of exercisable stock options (shares) | shares 13,149
Exercisable stock options, weighted average exercise price (dollars per share) $ 16.01