Annual report pursuant to Section 13 and 15(d)

Stock Compensation (Narrative) (Details)

v3.8.0.1
Stock Compensation (Narrative) (Details) - USD ($)
1 Months Ended 12 Months Ended 84 Months Ended
Mar. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2017
Dec. 31, 2015
May 19, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Number of options outstanding   1,172,659 922,930 1,172,659 721,924  
Unrecognized compensation expense related to stock options   $ 190,000   $ 190,000    
Aggregate intrinsic value of options outstanding   0   $ 0    
Intrinsic value of all options exercised   0 $ 0      
Net cash proceeds from exercise of stock options   0 0      
Share based compensation expense before income taxes   417,000 632,000      
Share based compensation expense after income taxes   271,000 411,000      
Excess tax benefits from exercise of stock options   $ 0 $ 0      
Shares of ESOP allocated to accounts of eligible employees   696,688   696,688    
2011 Executive Incentive Compensation Plan [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Number of awards authorized           2,000,000
Number of options granted   288,186        
Award expiration period   7 years        
Shares issued under Plan   165,054   165,054    
Number of options outstanding   1,315,294   1,315,294    
Awards eligible for grant   519,652   519,652    
2011 Executive Incentive Compensation Plan [Member] | Share-based Compensation Award, Tranche One [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Award vesting percentage   25.00%        
1992 Stock Plan [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Number of options granted       0    
Awards eligible for grant   10,230   10,230    
ESOP [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Award vesting period   6 years        
Initial award vesting period   2 years        
Requisite service period   1 year        
ESOP [Member] | Share-based Compensation Award, Tranche One [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Award vesting percentage   20.00%        
2017 ESOP [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
ESOP contributions   $ 425,890        
Issuance of common stock to Employee Stock Ownership Plan, Shares 119,632          
2016 ESOP [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
ESOP contributions   $ 218,758        
Issuance of common stock to Employee Stock Ownership Plan, Shares   47,248        
Non-Employee Directors [Member] | Stock Option Plan For Directors [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Number of options granted       0    
Award expiration period   10 years        
Number of options outstanding   51,000   51,000    
Number of shares automatically granted to each non-employee director   3,000        
Employee Stock Option [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Recognition period for unrecognized compensation expense   2 years 3 months 18 days        
Performance Units [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Unrecognized compensation expense for awards   $ 22,000   $ 22,000    
Recognition period for unrecognized compensation expense   1 year 1 month 6 days        
Employee Stock Purchase Plan [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Percentage of price of common stock at which employees are able to acquire   85.00%        
Awards eligible for grant   53,205   53,205    
Restricted Stock Units (RSUs) [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Unrecognized compensation expense for awards   $ 0   $ 0    
2017 to 2019 [Member] | Performance Units [Member] | Key Employees [Member] | 2011 Executive Incentive Compensation Plan [Member]            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Deferred stock awards granted   90,789