Quarterly report pursuant to Section 13 or 15(d)

LIABILITIES AND LONG-TERM DEBT LIABILITIES AND LONG-TERM DEBT - Additional Information (Details)

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LIABILITIES AND LONG-TERM DEBT LIABILITIES AND LONG-TERM DEBT - Additional Information (Details) - USD ($)
6 Months Ended
Oct. 01, 2014
Jun. 30, 2018
Dec. 31, 2017
Jul. 25, 2017
Jul. 24, 2017
Line of Credit Facility [Line Items]          
Long-term debt outstanding   $ 105,416,000 $ 99,583,000    
Current portion of long-term debt   8,061,000 8,061,000    
Total long-term debt, less current portion including loan fees   97,015,000 91,021,000    
Debt issuance costs   $ (340,000) $ (501,000)    
Interest rate on loan   4.38% 4.07%    
Minimum [Member]          
Line of Credit Facility [Line Items]          
Commitment fee   0.25%      
Maximum [Member]          
Line of Credit Facility [Line Items]          
Commitment fee   0.375%      
Acquisition Term Loan [Member]          
Line of Credit Facility [Line Items]          
Long-term debt outstanding   $ 43,750,000 $ 47,250,000    
Total long-term debt $ 70,000,000        
Amortization period for principal on acquisition term loan   10 years      
Principal payable   $ 1,800,000      
Current portion of long-term debt   7,000,000 7,000,000    
Total long-term debt, less current portion including loan fees   36,800,000 40,300,000    
Term Loan [Member]          
Line of Credit Facility [Line Items]          
Long-term debt outstanding   16,666,000 17,333,000    
Principal payable   300,000      
Current portion of long-term debt   1,300,000 1,300,000    
Total long-term debt, less current portion including loan fees   15,700,000 16,000,000    
Amount of multiple advance loan that was available to be borrowed   25,000,000      
Revolving Credit Facility [Member]          
Line of Credit Facility [Line Items]          
Maximum borrowing capacity   60,000,000.0   $ 60,000,000 $ 40,000,000
Long-term debt outstanding   45,000,000 $ 35,000,000    
Available remaining borrowing capacity   14,900,000      
Available remaining borrowing capacity to maintain covenant compliance   $ 10,000,000