EQT GP Holdings, LP (Details) - USD ($) $ / shares in Units, $ in Thousands					3 Months Ended	6 Months Ended	12 Months Ended
	Jan. 18, 2018	Nov. 16, 2015	May 15, 2015	Mar. 17, 2015	Dec. 31, 2017	Dec. 31, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Class of Stock [Line Items]
Net proceeds from sale of units							$ 0	$ 217,102	$ 1,182,002
Increase to deferred tax liability		$ 31,300		$ 73,500		$ 7,400		$ 15,000
Cash distribution declared (in dollars per share)					$ 0.2917
Cash distribution declared, limited partner					$ 8,400
Limited Partner Common
Class of Stock [Line Items]
Limited partner interest			90.10%
EQGP
Class of Stock [Line Items]
Percentage of all incremental cash distributed (up to)					48.00%		48.00%
Net proceeds from sale of units			$ 674,000
Increase (decrease) in ownership of EQT GP Holdings, LP			(512,900)
Increase to deferred tax liability			192,500
EQGP | Subsequent Event
Class of Stock [Line Items]
Cash distribution declared (in dollars per share)	$ 0.244
Cash distribution declared, limited partner	$ 64,900
EQGP | Common Stock
Class of Stock [Line Items]
Increase (decrease) in ownership of EQT GP Holdings, LP			$ 320,400
EQGP | Limited Partner Common
Class of Stock [Line Items]
Limited partner interest			9.90%
Underwriter's discount			$ 37,500
Structuring fees			$ 2,700
EQGP | Limited Partner Common | Affiliated Entity
Class of Stock [Line Items]
Number of common units (in shares)					21,811,643		21,811,643
Limited partner interest							26.60%
EQGP | General Partner
Class of Stock [Line Items]
General partner interest							1.80%
EQGP | General Partner | Affiliated Entity
Class of Stock [Line Items]
Number of general partner units (in shares)					1,443,015		1,443,015
EQGP | General Partner Common
Class of Stock [Line Items]
Incentive distribution rights distributed in respect of each common unit and general partner unit (in dollars per share)							$ 0.525