Commitments and Contingencies Additional information (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($) MMcf	Jun. 30, 2017 USD ($)
Loss Contingencies [Line Items]
Results of Operations, Transportation Costs	$ 8,964	$ 6,488	$ 16,277	$ 12,390
First facilities agreement with midstream provider [Member]
Loss Contingencies [Line Items]
incremental volume commitment | MMcf			51.5
Delaware Basin/Wattenberg Field [Member]
Loss Contingencies [Line Items]
Results of Operations, Transportation Costs	$ 2,600	$ 2,600	$ 5,200	$ 4,800