Commitments and Contingencies Additional information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018 USD ($) MMcf	Mar. 31, 2017 USD ($)
Loss Contingencies [Line Items]
Transportation, gathering, and processing expenses	$ 7,313	$ 5,902
First facilities agreement with midstream provider [Member]
Loss Contingencies [Line Items]
incremental volume commitment | MMcf	51.5
Utica Shale natural gas and Wattenberg Field crude oil [Member]
Loss Contingencies [Line Items]
Transportation, gathering, and processing expenses	$ 2,600	$ 2,200