EQT Midstream Partners, LP (Details) (USD $) In Thousands, except Share data, unless otherwise specified	6 Months Ended		0 Months Ended	3 Months Ended	6 Months Ended	0 Months Ended
	Jun. 30, 2013	Jul. 02, 2012 Equitrans	Jul. 02, 2012 EQT Midstream Partners	Jun. 30, 2013 EQT Midstream Partners	Jun. 30, 2013 EQT Midstream Partners	Jul. 22, 2013 EQT Midstream Partners Subsequent Event
Subsidiary or equity method investee
Number of common units issued to the public in an offering (in shares)			14,375,000			12,650,000
Common units issued to the public in an offering as a percentage of outstanding equity			40.60%
Ownership percentage			59.40%			44.60%
Common units (in shares)			2,964,718			3,443,902
Subordinated units (in shares)			17,339,718			17,339,718
General partner's interest (as a percent)			2.00%			2.00%
Percentage of ownership contributed		100.00%
Distributions paid to noncontrolling interest	$ 10,350			$ 5,300	$ 10,400
Distributions to noncontrolling interests (in dollars per common unit)	$ 0.72			$ 0.37	$ 0.72