Subsequent Event (Details) Mcfe in Thousands, $ in Thousands			12 Months Ended
	Feb. 08, 2017 USD ($) a Mcfe well mi	Feb. 01, 2017 USD ($) a	Dec. 31, 2016 USD ($) a well	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Subsequent Event [Line Items]
Number of acres acquired (in acres)			145,500
Payment for acquisition | $			$ 1,051,239	$ 0	$ 174,184
Number of wells acquired | well			75
Subsequent Event
Subsequent Event [Line Items]
Payment for acquisition | $	$ 527,000
Production of well (in MMcfe) | Mcfe	80
Number of miles of pipeline acquired | mi	20
Subsequent Event | Bankruptcy Auction
Subsequent Event [Line Items]
Number of acres acquired, core development area	53,400
Number of wells acquired | well	174
Number of acres acquired, outside core development area	32,000
Subsequent Event | Marion, Monongalia, and Wetzel Counties
Subsequent Event [Line Items]
Number of acres acquired (in acres)		14,000
Payment for acquisition | $		$ 130,000