Quarterly report pursuant to Section 13 or 15(d)

REVOLVING LINE OF CREDIT (Details Textual)

v3.19.1
REVOLVING LINE OF CREDIT (Details Textual) - USD ($)
 3 Months Ended 12 Months Ended
Apr. 09, 2019
Mar. 31, 2019
Dec. 31, 2018
Jun. 01, 2018
Jul. 01, 2014
Line of Credit Facility [Line Items]          
Line of Credit Facility, Interest Rate Description   The annual interest rate on each Base Rate Loan is (a) the greatest of (i) the Administrative Agent’s prime lending rate, (ii) the federal funds rate plus 0.5% per annum or the (iii) adjusted LIBOR determined on a daily basis for an interest period of one-month, plus 1.00% per annum, plus (b) a margin between 2.75% and 3.75% (depending on the then-current level of borrowing base usage).      
Leverage Ratio, Total   4.0 to 1.0      
Minimum Leverage Ratio Current   1.0 to 1.0      
Debt Instrument, Redemption, Description   The Borrowing Base will be redetermined semi-annually on each May 1 and November 1      
Long-term Line of Credit   $ 84,500,000 $ 39,500,000    
Minimum [Member]          
Line of Credit Facility [Line Items]          
Line of Credit Facility, Maximum Borrowing Capacity       $ 60,000,000  
Debt Instrument, Basis Spread on Variable Rate   1.75%      
Maximum [Member]          
Line of Credit Facility [Line Items]          
Line of Credit Facility, Maximum Borrowing Capacity         $ 175,000,000
Debt Instrument, Basis Spread on Variable Rate   2.75%      
Revolving Credit Facility [Member]          
Line of Credit Facility [Line Items]          
Line of Credit Facility, Maximum Borrowing Capacity     $ 500,000,000    
Line of Credit Facility, Expiration Date     Jun. 26, 2020    
Revolving Credit Facility [Member] | Subsequent Event [Member]          
Line of Credit Facility [Line Items]          
Line of Credit Facility, Expiration Period 5 years        
Revolving Credit Facility [Member] | Minimum [Member] | Subsequent Event [Member]          
Line of Credit Facility [Line Items]          
Line of Credit Facility, Maximum Borrowing Capacity $ 425,000,000        
Revolving Credit Facility [Member] | Maximum [Member] | Subsequent Event [Member]          
Line of Credit Facility [Line Items]          
Line of Credit Facility, Maximum Borrowing Capacity $ 1,000,000,000