Derivative Financial Instruments (Details 2) $ in Thousands	Mar. 31, 2018 USD ($) bbl $ / bbl	Dec. 31, 2017 USD ($)
Summary of gross liability balances of derivative instruments
Total	$ (4,823)	$ (15,239)
Gross amounts netted in the condensed consolidated balance sheets	0	0
Net amounts presented in the condensed consolidated balance sheets	(4,823)	(15,239)
Current assets
Derivative [Line Items]
Gross amounts of recognized assets	109,635	131,092
Gross amounts netted in the condensed consolidated balance sheets	(109,155)	(129,902)
Oil, natural gas and natural gas liquids (NGL) derivatives	480	1,190
Other assets
Derivative [Line Items]
Gross amounts of recognized assets	5,835
Gross amounts netted in the condensed consolidated balance sheets	(5,835)
Oil, natural gas and natural gas liquids (NGL) derivatives	0
Current liabilities
Summary of gross liability balances of derivative instruments
Gross amounts of recognized liabilities	(114,046)	(146,331)
Gross amounts netted in the condensed consolidated balance sheet	109,155	129,902
Oil, natural gas and natural gas liquids (NGL) derivatives	(4,891)	$ (16,429)
Other liabilities
Summary of gross liability balances of derivative instruments
Gross amounts of recognized liabilities	(6,247)
Gross amounts netted in the condensed consolidated balance sheet	5,835
Oil, natural gas and natural gas liquids (NGL) derivatives	(412)
Open Costless Collar Contracts
Summary of gross liability balances of derivative instruments
Derivative Assets (Liabilities), at Fair Value, Net	$ (15,179)
Derivative Contract, Calculation Period One | Oil - WTI | Open Three-way Costless Collar Contracts
Derivative [Line Items]
Notional Quantity (Bbl or MMBtu) | bbl	1,440,000
Summary of gross liability balances of derivative instruments
Derivative, Floor Price | $ / bbl	50.08
Derivative Assets (Liabilities), at Fair Value, Net	$ (1,196)
Derivative Contract, Calculation Period One | Oil - WTI | Open Costless Collar Contracts
Derivative [Line Items]
Notional Quantity (Bbl or MMBtu) | bbl	2,160,000
Summary of gross liability balances of derivative instruments
Derivative, Floor Price | $ / bbl	44.27
Derivative, Cap Price | $ / bbl	60.29
Derivative Assets (Liabilities), at Fair Value, Net	$ (11,663)