Annual report pursuant to Section 13 and 15(d)

Benefit Plans and Collective Bargaining Agreements (Details)

v3.19.1
Benefit Plans and Collective Bargaining Agreements (Details) - USD ($)
 12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Defined Contribution Plan Disclosure [Line Items]      
Total employer contributions to plans under collective-bargaining arrangements $ 32,034 $ 29,042 $ 22,256
401(k) Employee Stock Ownership Plan      
Defined Contribution Plan Disclosure [Line Items]      
Employee maximum contribution percentage 100.00%    
Employee maximum contribution amount $ 18,500    
Minimum age to qualify under Economic Growth and Tax Relief Reconciliation Act 50 years    
Employee additional contribution eligible under Economic Growth and Tax Relief Reconciliation Act $ 6,000    
Employee maximum contribution eligible under Economic Growth and Tax Relief Reconciliation Act $ 24,500    
Employer maximum contribution percentage match 100.00%    
Matching percentage by employer of employees' gross pay 4.00%    
Matching contributions made by employer $ 694,795 608,473 516,991
Employer discretionary contribution $ 0 0 0
401(k) and Profit Sharing Plan      
Defined Contribution Plan Disclosure [Line Items]      
Employee maximum contribution percentage 60.00%    
Employee maximum contribution amount $ 18,500    
Minimum age to qualify under Economic Growth and Tax Relief Reconciliation Act 50 years    
Employee additional contribution eligible under Economic Growth and Tax Relief Reconciliation Act $ 6,000    
Employee maximum contribution eligible under Economic Growth and Tax Relief Reconciliation Act $ 24,500    
Employer contribution as a percentage of participant's eligible compensation 3.00%    
Matching contributions made by employer $ 215,778 174,229 136,763
Employer discretionary contribution $ 0 0 $ 0
Maximum | Other Pension, Postretirement and Supplemental Plans      
Defined Contribution Plan Disclosure [Line Items]      
Funding percentage under defined benefit plans 80.00%    
Employer contribution percentage of each participant's eligible compensation 4.00%    
Employer's contribution percentage of total contributions 5.00%    
Employer contributions to defined benefit plans $ 129,403 $ 69,245