Fair Value Measurement - Quantitative Information about Level 3 Inputs (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2017 USD ($) $ / bbl
Natural gas liquids | Swaps | Low
Commodity Derivative Instruments - Assets
Price (in dollars per barrel)	18.06
Natural gas liquids | Swaps | High
Commodity Derivative Instruments - Assets
Price (in dollars per barrel)	72.52
Oil | Swaps | Low
Commodity Derivative Instruments - Assets
Price (in dollars per barrel)	44.60
Oil | Swaps | High
Commodity Derivative Instruments - Assets
Price (in dollars per barrel)	85.60
Discounted cash flow approach | Level 3 | Natural gas liquids | Swaps
Commodity Derivative Instruments - Assets
Fair Value | $	$ (1,266)
Discounted cash flow approach | Level 3 | Natural gas liquids | Swaps | Low
Commodity Derivative Instruments - Assets
Price (in dollars per barrel)	22.89
Discounted cash flow approach | Level 3 | Natural gas liquids | Swaps | High
Commodity Derivative Instruments - Assets
Price (in dollars per barrel)	23.94
Discounted option model approach | Level 3 | Oil | Collars
Commodity Derivative Instruments - Assets
Fair Value | $	$ 1,988
Discounted option model approach | Level 3 | Oil | Collars | Low
Commodity Derivative Instruments - Assets
Price (in dollars per barrel)	45.00
Discounted option model approach | Level 3 | Oil | Collars | High
Commodity Derivative Instruments - Assets
Price (in dollars per barrel)	61.00
Discounted option model approach | Level 3 | Natural gas | Collars
Commodity Derivative Instruments - Assets
Fair Value | $	$ (984)
Discounted option model approach | Level 3 | Natural gas | Collars | Low
Commodity Derivative Instruments - Assets
Price (in dollars per barrel)	2.55
Discounted option model approach | Level 3 | Natural gas | Collars | High
Commodity Derivative Instruments - Assets
Price (in dollars per barrel)	3.41