XML 32 R21.htm IDEA: XBRL DOCUMENT v3.7.0.1
Credit Arrangement (Details)
$ in Millions
6 Months Ended
Jun. 30, 2017
USD ($)
Credit Agreement [Member]  
Line of Credit Facility [Line Items]  
Maximum borrowing capacity $ 60.0
Reduction in borrowing base due to deficit in fixed charges coverage ratio test $ 6.0
Number of trailing months to compute fixed charges coverage ratio 12 months
Current borrowing base $ 51.8
Net availability $ 45.8
Maturity date Mar. 31, 2021
Letter of Credit [Member]  
Line of Credit Facility [Line Items]  
Outstanding letters of credit $ 0.0