Summary of Significant Accounting Policies - Schedule of Regulated Net Revenues and Operating Expenses (Details) - EQT Midstream - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Net revenues	$ 309,984	$ 267,997	$ 184,767
Operating expenses	$ 109,954	$ 89,617	$ 71,517