Derivative Instruments - Commodity derivatives (Details)	Sep. 30, 2016 bbl / d MMBTU / d $ / bbl $ / gal $ / MMBTU
TCOminusNYMEX | Three months ending December 31, 2016 | Basis Differential Positions
Derivative Instruments
Notional amount (MMBtu/Bbls per day)	290,000
Weighted average index price | $ / MMBTU	(0.45)
TCOminusNYMEX | Year ending December 31, 2017 | Basis Differential Positions
Derivative Instruments
Notional amount (MMBtu/Bbls per day)	125,000
Weighted average index price | $ / MMBTU	(0.49)
NYMEXminusTCO | Three months ending December 31, 2016 | Basis Differential Positions
Derivative Instruments
Notional amount (MMBtu/Bbls per day)	170,000
Weighted average index price | $ / MMBTU	0.34
NYMEXminusTCO | Year ending December 31, 2017 | Basis Differential Positions
Derivative Instruments
Notional amount (MMBtu/Bbls per day)	125,000
Weighted average index price | $ / MMBTU	0.30
Swaps | Natural gas | Three months ending December 31, 2016
Derivative Instruments
Notional amount (MMBtu/Bbls per day)	1,612,500
Swaps | Natural gas | Year 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 | TCO | Three months ending December 31, 2016
Derivative Instruments
Notional amount (MMBtu/Bbls per day)	60,000
Weighted average index price | $ / MMBTU	5.01
Swaps | Natural gas | Dominion South | Three months ending December 31, 2016
Derivative Instruments
Notional amount (MMBtu/Bbls per day)	272,500
Weighted average index price | $ / MMBTU	5.47
Swaps | Natural gas | NYMEX | Three months ending December 31, 2016
Derivative Instruments
Notional amount (MMBtu/Bbls per day)	1,110,000
Weighted average index price | $ / MMBTU	3.57
Swaps | Natural gas | NYMEX | Year ending December 31, 2017
Derivative Instruments
Notional amount (MMBtu/Bbls per day)	1,370,000
Weighted average index price | $ / MMBTU	3.39
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	3.91
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	3.70
Swaps | Natural gas | NYMEX | Year ending December 31, 2020
Derivative Instruments
Notional amount (MMBtu/Bbls per day)	1,377,500
Weighted average index price | $ / MMBTU	3.66
Swaps | Natural gas | NYMEX | Year Ending December 31, 2021
Derivative Instruments
Notional amount (MMBtu/Bbls per day)	660,000
Weighted average index price | $ / MMBTU	3.35
Swaps | Natural gas | NYMEX | Year ending December 31, 2022
Derivative Instruments
Notional amount (MMBtu/Bbls per day)	470,000
Weighted average index price | $ / MMBTU	3.26
Swaps | Natural gas | CGTLA | Three months ending December 31, 2016
Derivative Instruments
Notional amount (MMBtu/Bbls per day)	170,000
Weighted average index price | $ / MMBTU	4.20
Swaps | Natural gas | CGTLA | Year ending December 31, 2017
Derivative Instruments
Notional amount (MMBtu/Bbls per day)	420,000
Weighted average index price | $ / MMBTU	4.27
Swaps | Natural gas | CCG | Year ending December 31, 2017
Derivative Instruments
Notional amount (MMBtu/Bbls per day)	70,000
Weighted average index price | $ / MMBTU	4.57
Swaps | Natural gas liquids | Three months ending December 31, 2016
Derivative Instruments
Notional amount (MMBtu/Bbls per day) | bbl / d	30,000
Swaps | Natural gas liquids | Year 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	2,000
Swaps | Ethane | Mont Belvieu-Ethane | Year 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, 2016
Derivative Instruments
Notional amount (MMBtu/Bbls per day) | bbl / d	30,000
Weighted average index price | $ / gal	0.61
Swaps | Propane | Mont Belvieu-Propane | Year ending December 31, 2017
Derivative Instruments
Notional amount (MMBtu/Bbls per day) | bbl / d	27,500
Weighted average index price | $ / gal	0.39
Swaps | Propane | Mont Belvieu-Propane | Year ending December 31, 2018
Derivative Instruments
Notional amount (MMBtu/Bbls per day) | bbl / d	2,000
Weighted average index price | $ / gal	0.65
Swaps | Oil | Year ending December 31, 2017
Derivative Instruments
Notional amount (MMBtu/Bbls per day) | bbl / d	1,000
Swaps | Oil | WTI-NYMEX member | Year ending December 31, 2017
Derivative Instruments
Notional amount (MMBtu/Bbls per day) | bbl / d	1,000
Weighted average index price | $ / bbl	51.90