Annual report pursuant to Section 13 and 15(d)

Long-term Debt (Line of Credit) (Details)

v3.8.0.1
Long-term Debt (Line of Credit) (Details) - Revolving Line of Credit [Member] - USD ($)
 12 Months Ended
Aug. 31, 2016
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Oct. 30, 2017
Line of Credit Facility [Line Items]          
Line of credit, average outstanding amount   $ 27,895,901 $ 6,830,114    
Line of credit, weighted average interest rate (percent)   3.09% 2.88%    
Interest payments   $ 856,651 $ 826,478 $ 1,149,163  
ABL line of credit, due October 30, 2020 [Member]          
Line of Credit Facility [Line Items]          
Long-term Debt   25,913,557 $ 8,804,206    
Line of credit, maximum borrowing capacity   $ 56,726,959     $ 65,000,000
Line of credit, increase to limit         $ 20,000,000
Variable rate basis LIBOR        
Stated interest rate (percent)   3.44%      
Unused capacity fee on line of credit (percent)   0.125%      
Line of credit, amount borrowed   $ 25,913,557      
Line of credit, remaining availability   $ 30,813,402      
Revolving line of credit due November 21, 2017 [Member]          
Line of Credit Facility [Line Items]          
Unused capacity fee on line of credit (percent)     0.125% 0.125%  
ABL line of credit, due February 28, 2019 [Member]          
Line of Credit Facility [Line Items]          
Line of credit, maximum borrowing capacity $ 45,000,000        
Stated interest rate (percent)     2.62%