Summary of Significant Accounting Policies - Major Customers and Associated Percentage of Revenue (Detail) - Sales Revenue, Net [Member] - Customer Concentration Risk [Member]	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenue, Major Customer [Line Items]
Major customers and associated percentage of revenue	63.00%	70.00%	72.00%
Antero Resources Corporation [Member]
Revenue, Major Customer [Line Items]
Major customers and associated percentage of revenue	14.00%	19.00%	47.00%
ARM Energy Management [Member]
Revenue, Major Customer [Line Items]
Major customers and associated percentage of revenue		11.00%	25.00%
Concord Energy, LLC [Member]
Revenue, Major Customer [Line Items]
Major customers and associated percentage of revenue	12.00%
Enlink Midstream Operating [Member]
Revenue, Major Customer [Line Items]
Major customers and associated percentage of revenue	17.00%	21.00%
Sequent Energy Management [Member]
Revenue, Major Customer [Line Items]
Major customers and associated percentage of revenue	20.00%	19.00%