Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	$ 7,182	$ 34,932
Derivative assets	2,756	10,100
Liabilities:
Commodity derivative liabilities – current	14,203	991
Derivative Liability, Noncurrent	2,201	0
Fair Value, Measurements, Recurring | Commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	7,182	34,932
Derivative assets	2,756	10,100
Liabilities:
Commodity derivative liabilities – current	(14,203)	(991)
Derivative Liability, Noncurrent	2,201	0
Fair Value, Measurements, Recurring | Commodity contracts | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Derivative assets	0	0
Liabilities:
Commodity derivative liabilities – current	0	0
Derivative Liability, Noncurrent	0	0
Fair Value, Measurements, Recurring | Commodity contracts | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	7,182	34,932
Derivative assets	2,756	10,100
Liabilities:
Commodity derivative liabilities – current	(14,203)	(991)
Derivative Liability, Noncurrent	2,201	0
Fair Value, Measurements, Recurring | Commodity contracts | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Derivative assets	0	0
Liabilities:
Commodity derivative liabilities – current	0	0
Derivative Liability, Noncurrent	$ 0	$ 0
Crude Oil | Commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Third-party quoted forward prices	WTI
Louisiana Light Sweet [Member] | Commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Third-party quoted forward prices	LLS
MEH [Domain] | Commodity contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Third-party quoted forward prices	MEH