Quarterly report pursuant to Section 13 or 15(d)

Derivatives and Fair Value (Effect of Derivative Instruments on the Condensed Consolidated Statements of Operations) (Details)

v3.19.3
Derivatives and Fair Value (Effect of Derivative Instruments on the Condensed Consolidated Statements of Operations) (Details) - Crude Oil Swaps [Member] - USD ($)
$ in Thousands
3 Months Ended 9 Months Ended
Sep. 30, 2019
Sep. 30, 2018
Sep. 30, 2019
Sep. 30, 2018
Derivative Instruments, Gain (Loss) [Line Items]        
Derivative, gain (loss) $ 2,267 $ (1,026) $ 2,266 $ (2,036)
Realized Gain - Contract Settlements [Member]        
Derivative Instruments, Gain (Loss) [Line Items]        
Derivative, gain (loss) 493 39 2,056 28
Unrealized (Gain) Loss [Member]        
Derivative Instruments, Gain (Loss) [Line Items]        
Derivative, gain (loss) $ 1,774 $ (1,065) $ 210 $ (2,064)