Derivative Instruments - Commodity derivatives (Details)	Sep. 30, 2017 bbl / d MMBTU / d $ / gal $ / bbl $ / MMBTU
TCOminusNYMEX | Year ending December 31, 2017 | Basis Differential Positions
Derivative Instruments
Notional amount (MMBtu/Bbls per day)	125,000
Weighted average index price | $ / MMBTU	0.51
NYMEXminusTCO | Year ending December 31, 2017 | Basis Differential Positions
Derivative Instruments
Notional amount (MMBtu/Bbls per day)	125,000
Weighted average index price | $ / MMBTU	0.39
Swaps | Natural gas | Three months ending December 31, 2017
Derivative Instruments
Notional amount (MMBtu/Bbls per day)	1,860,000
Swaps | Natural gas | Year ending December 31, 2018
Derivative Instruments
Notional amount (MMBtu/Bbls per day)	2,002,500
Swaps | Natural gas | NYMEX | Three months ending December 31, 2017
Derivative Instruments
Notional amount (MMBtu/Bbls per day)	1,370,000
Weighted average index price | $ / MMBTU	3.46
Swaps | Natural gas | NYMEX | Year ending December 31, 2018
Derivative Instruments
Notional amount (MMBtu/Bbls per day)	2,002,500
Weighted average index price | $ / MMBTU	3.50
Swaps | Natural gas | NYMEX | Year ending December 31, 2019
Derivative Instruments
Notional amount (MMBtu/Bbls per day)	2,330,000
Weighted average index price | $ / MMBTU	3.50
Swaps | Natural gas | NYMEX | Year ending December 31, 2020
Derivative Instruments
Notional amount (MMBtu/Bbls per day)	1,417,500
Weighted average index price | $ / MMBTU	3.25
Swaps | Natural gas | NYMEX | Year Ending December 31, 2021
Derivative Instruments
Notional amount (MMBtu/Bbls per day)	710,000
Weighted average index price | $ / MMBTU	3.00
Swaps | Natural gas | NYMEX | Year ending December 31, 2022
Derivative Instruments
Notional amount (MMBtu/Bbls per day)	850,000
Weighted average index price | $ / MMBTU	3.00
Swaps | Natural gas | NYMEX | Year ending December 31, 2023
Derivative Instruments
Notional amount (MMBtu/Bbls per day)	90,000
Weighted average index price | $ / MMBTU	2.91
Swaps | Natural gas | CGTLA | Three months ending December 31, 2017
Derivative Instruments
Notional amount (MMBtu/Bbls per day)	420,000
Weighted average index price | $ / MMBTU	4.37
Swaps | Natural gas | CCG | Three months ending December 31, 2017
Derivative Instruments
Notional amount (MMBtu/Bbls per day)	70,000
Weighted average index price | $ / MMBTU	4.68
Swaps | Natural gas liquids | Three months ending December 31, 2017
Derivative Instruments
Notional amount (MMBtu/Bbls per day) | bbl / d	47,500
Swaps | Natural gas liquids | Year ending December 31, 2018
Derivative Instruments
Notional amount (MMBtu/Bbls per day) | bbl / d	3,000
Swaps | Ethane | Mont Belvieu-Ethane | Three months ending December 31, 2017
Derivative Instruments
Notional amount (MMBtu/Bbls per day) | bbl / d	20,000
Weighted average index price | $ / gal	0.25
Swaps | Propane | Mont Belvieu-Propane | Three months ending December 31, 2017
Derivative Instruments
Notional amount (MMBtu/Bbls per day) | bbl / d	27,500
Weighted average index price | $ / gal	0.40
Swaps | Propane | Mont Belvieu-Propane | Year ending December 31, 2018
Derivative Instruments
Notional amount (MMBtu/Bbls per day) | bbl / d	3,000
Weighted average index price | $ / gal	0.67
Swaps | Oil | Three months ending December 31, 2017
Derivative Instruments
Notional amount (MMBtu/Bbls per day) | bbl / d	3,000
Swaps | Oil | Year ending December 31, 2018
Derivative Instruments
Notional amount (MMBtu/Bbls per day) | bbl / d	1,000
Weighted average index price | $ / bbl	49.96
Swaps | Oil | WTI-NYMEX member | Three months ending December 31, 2017
Derivative Instruments
Notional amount (MMBtu/Bbls per day) | bbl / d	3,000
Weighted average index price | $ / bbl	54.75