Annual report pursuant to Section 13 and 15(d)

Note 6 - Debt (Details Textual)

v3.8.0.1
Note 6 - Debt (Details Textual)
3 Months Ended 6 Months Ended 12 Months Ended
Dec. 05, 2016
USD ($)
Mar. 23, 2015
USD ($)
Dec. 31, 2017
USD ($)
Sep. 30, 2017
USD ($)
Jun. 30, 2017
USD ($)
Mar. 31, 2017
USD ($)
Jun. 30, 2017
USD ($)
Dec. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
Jun. 28, 2017
USD ($)
Jun. 27, 2017
USD ($)
Mar. 22, 2017
Long-term Debt     $ 28,391,000         $ 28,391,000 $ 31,891,000      
Proceeds from Issuance of Long-term Debt               28,866,000 66,892,000      
Debt Instrument, Periodic Payment, Principal     577,500 $ 577,500     $ 577,500          
Leverage Ratio           2.96            
Debt Instrument, Periodic Payment     766,650 $ 766,650 $ 766,650 $ 766,650            
Revolving Credit Facility [Member]                        
Long-term Line of Credit                  
The Chase Credit Agreement [Member] | London Interbank Offered Rate (LIBOR) [Member]                        
Debt Instrument, Basis Spread on Variable Rate               2.75%        
Debt Instrument, Basis Spread on Variable Rate, Before Margin Rate               2.50%        
Debt Instrument, Interest Rate, Effective Percentage     4.32%         4.32%        
Debt Instrument, Floor Rate               1.57%        
The Chase Credit Agreement [Member] | London Interbank Offered Rate (LIBOR) [Member] | Minimum [Member]                        
Debt Instrument, Basis Spread on Variable Rate               2.00%        
Applicable Margin Rate               (1.00%)        
The Chase Credit Agreement [Member] | London Interbank Offered Rate (LIBOR) [Member] | Maximum [Member]                        
Applicable Margin Rate               0.25%        
The Chase Credit Agreement [Member] | Eurodollar [Member] | Maximum [Member]                        
Debt Instrument, Basis Spread on Variable Rate               3.00%        
The Chase Credit Agreement [Member] | JP Morgan Chase Bank [Member]                        
Debt Instrument, Maturity Date   Mar. 23, 2020                    
The Chase Credit Agreement [Member] | JP Morgan Chase Bank [Member] | Revolving Credit Facility [Member]                        
Line of Credit Facility, Maximum Borrowing Capacity   $ 10,000,000                    
First Amended Credit Agreement [Member]                        
Maximum Permitted Leverage Ratio, Period One 2.75                      
Maximum Permitted Leverage Ratio, Period Two 2.5                      
Maximum Permitted Leverage Ratio, Period Three 2.25                      
Second Amended Credit Agreement [Member]                        
Maximum Permitted Leverage Ratio, Period One                       2.75
Maximum Permitted Leverage Ratio, Period Two                       2.5
Maximum Permitted Leverage Ratio, Period Three                       2.25
Third Amended Credit Agreement [Member]                        
Maximum Permitted Leverage Ratio, Period One     4         4        
Maximum Permitted Leverage Ratio, Period Two     3.75         3.75        
Maximum Permitted Leverage Ratio, Period Three     3.5         3.5        
Debt Instrument, Face Amount                   $ 2,500,000 $ 5,000,000  
Long-term Line of Credit     $ 30,665,999.98         $ 30,665,999.98        
Percentage of Excess Cash Flow for Prepayment of Debt, If Leverage Ratio is Greater Than or Equal To 2.5     75.00%         75.00%        
Percentage of Excess Cash Flow for Prepayment of Debt, If Leverage Ratio is Less Than 2.5 But Greater Than or Equal To 2.0     50.00%         50.00%        
Percentage of Excess Cash Flow for Prepayment of Debt, If Leverage Ratio is Less Than 2.0     0.00%         0.00%        
Maximum Permitted Leverage Ratio, Period Four     3         3        
Maximum Permitted Fixed Charges Coverage Ratio, Period One     1.15         1.15        
Minimum Permitted Fixed Charges Coverage Ratio, Period Two     1.25         1.25        
Debt Instrument, Interest Rate, Increase (Decrease)               0.50%        
Third Amended Credit Agreement [Member] | Revolving Credit Facility [Member]                        
Debt Instrument, Face Amount                   5,000,000 10,000,000  
Third Amended Credit Agreement [Member] | JP Morgan Chase Bank [Member] | Revolving Credit Facility [Member]                        
Debt Instrument, Face Amount                   $ 12,500,000 $ 25,000,000  
Term Loan A [Member] | The Chase Credit Agreement [Member] | JP Morgan Chase Bank [Member]                        
Long-term Debt   27,000,000                    
Proceeds from Issuance of Long-term Debt   27,000,000                    
Term Loan B [Member] | The Chase Credit Agreement [Member] | JP Morgan Chase Bank [Member]                        
Long-term Debt   8,000,000                    
Proceeds from Issuance of Long-term Debt   $ 8,000,000                    
Term Loan [Member]                        
Long-term Debt     $ 28,511,000         $ 28,511,000 $ 32,000,000      
Term Loan [Member] | The Chase Credit Agreement [Member]                        
Long-term Debt $ 32,000,000                      
Debt Agreement, Additional Amount Available 5,000,000                      
Debt Instrument, Periodic Payment, Principal 1,300,000                      
Term Loan [Member] | First Amended Credit Agreement [Member]                        
Debt Instrument, Face Amount $ 32,000,000