Annual report pursuant to Section 13 and 15(d)

Stock Plans and Management Compensation (Details 2)

v3.19.3.a.u2
Stock Plans and Management Compensation (Details 2) - $ / shares
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
$23.79 [Member]        
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]        
Share-based Payment Arrangement, Option, Exercise Price Range, Shares Outstanding 37,600      
Stock Options and SAR's [Member]        
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]        
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price $ 21.57 $ 16.04 $ 14.40 $ 14.43
Period for Stock Options and SARs to be Exercisable (in years) 10 years      
Awards Vesting Period (in years) 4 years      
Age of Grantee   62 years    
Stock Options and SAR's [Member] | $5.86 [Member]        
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]        
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price $ 11.08      
Share-based Payment Arrangement, Option, Exercise Price Range, Shares Outstanding 2,800      
Outstanding Options, Weighted Average Remaining Years of Contractual Life (in years) 1 month 6 days      
Stock Options and SAR's [Member] | $5.87 to $14.68 [Member]        
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]        
Share-based Payment Arrangement, Option, Exercise Price Range, Shares Outstanding 7,400      
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Exercise Price $ 14.68      
Outstanding Options, Weighted Average Remaining Years of Contractual Life (in years) 1 year 8 months 12 days      
Stock Options and SAR's [Member] | Greater Than $14.68 [Member]        
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]        
Share-based Payment Arrangement, Option, Exercise Price Range, Shares Outstanding 71,100      
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Exercise Price $ 21.52      
Outstanding Options, Weighted Average Remaining Years of Contractual Life (in years) 1 year 1 month 6 days      
Stock Options and SAR's [Member] | $23.79 [Member]        
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]        
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Exercise Price $ 23.79      
Outstanding Options, Weighted Average Remaining Years of Contractual Life (in years) 2 years 1 month 6 days